When to dive

Where to dive in July

307 dive destinations are at their peak in July, with another 234 in good shape. The strongest regions are Mediterranean, Cold Water, Coral Triangle; water runs from -2 °C to 34 °C (28–93 °F).

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At their peakGoodOther destinations

Warmest water: Kish Island22–34 °C (72–93 °F)
Clearest water: Silfra80 m (262 ft) visibility
Cold-water pick: Svalbard-2–6 °C (28–43 °F)

Mediterranean90 at their peak

Akamas Peninsula & Latchi
Cyprus
July to September brings the warmest sea; January to April is the coolest stretch, near 17 °C.
Water 17–28°C · 63–82°F
Alanya
Turkey
Boats run April to November, with the best conditions June to September and clearer water in autumn.
Water 17–29°C · 63–84°FVis 30 m · 100 ft
Alonissos & the Peristera Wreck
Greece
The underwater museum and most operators run May–Oct only; meltemi winds can close the exposed Peristera site in midsummer.
Sea 26°C · 79°FHigh 33°C · 91°FRain 19 mm · 0.7 inVis 40 m · 130 ft
Ayvalık & Cunda Islands
Turkey
The high season ends in September, and boats keep diving until the end of October.
Water 13–25°C · 55–77°F
Baia & the Phlegraean Fields
Italy
One Lucrino centre dives daily from May to October and on weekends from November to April; the sea is warmest in July and August.
Water 15–27°C · 59–81°FVis 20 m · 66 ft
Banyuls-sur-Mer & the Côte Vermeille
France
The Banyuls centres open year-round, but the sea averages 12 °C in February against 23 °C in August, the reserve's snorkel trail runs June to September, and the Tramontane can stop boats in any month.
Sea 22°C · 72°FHigh 32°C · 90°FRain 34 mm · 1.3 inVis 15 m · 50 ft
Bastia & Cap Corse (East Coast)
France
Centres run year round, but the sea tops 20 °C only from June to October; January–March sit at 14–15 °C.
Sea 26°C · 79°FHigh 34°C · 93°FRain 16 mm · 0.6 inVis 35 m · 115 ft
Batumi & the Adjarian Coast
Georgia
Late June to September is the window; September keeps August's warmth with thinner crowds, though rain can cloud the water.
Water 9–27°C · 48–81°FVis 10 m · 33 ft
Bergeggi, Noli, Spotorno & Finale Ligure
Italy
No closed season — the cutoff is wind, with grecale above roughly 15–18 knots stopping diving. Water falls to 13°C in February and peaks near 24°C in August.
Sea 25°C · 77°FHigh 30°C · 86°FRain 33 mm · 1.3 inVis 20 m · 66 ft
Bodrum
Turkey
Apr–Oct is the operating season with Jun–Sep warmest; the meltemi can blow hard through midsummer afternoons.
Sea 26°C · 79°FHigh 36°C · 97°FRain 2 mm · 0.1 inVis 35 m · 115 ft
Budva & Jaz
Montenegro
Boats run from April to October; June to August brings warm water and excellent visibility.
Water 14–26°C · 57–79°F
Buggerru & Pan di Zucchero
Italy
Across Sardinia the seas are calm from May to October; each dive is planned around the state of the sea.
Water 14–25°C · 57–77°F
Cabo de Gata-Níjar
Spain
Visitor season peaks spring through summer; surface water swings from 10-15 °C in winter to 21-30 °C in summer, with 22 °C still logged in October.
Sea 25°C · 77°FHigh 34°C · 93°FRain 2 mm · 0.1 inVis 25 m · 82 ft
Cabo de Palos & Islas Hormigas
Spain
Jun–Oct has the warmest water and the calmest crossings; winter is clearest but cold, and easterly winds close the seamounts year-round.
Sea 26°C · 79°FHigh 29°C · 84°FRain 4 mm · 0.2 inVis 20 m · 66 ft
Cabo Tiñoso (La Azohía, Isla Plana & Puerto de Mazarrón)
Spain
June to September is the comfortable window, and visibility can reach 30 m against a 15 m average; centres run trips year-round, with winter water near 15 °C.
Sea 26°C · 79°FHigh 34°C · 93°FRain 3 mm · 0.1 inVis 20 m · 66 ft
Cabrera Archipelago
Spain
Dive trips run mainly June to September, when the sea off Mallorca averages 22–26 °C; permits are limited, so book early.
Sea 26°C · 79°FHigh 28°C · 82°FRain 10 mm · 0.4 inVis 30 m · 100 ft
Cap d'Agde
France
Abyss Plongée opens March to December; the sea averages 12 °C in February and 22 °C in August, and the Tramontane or Mistral can stop the boats in any month.
Sea 22°C · 72°FHigh 35°C · 95°FRain 26 mm · 1.0 in
Cap de Creus
Spain
Jun–Sep is warmest and calmest; the Tramuntana blows hardest in winter and spring and regularly cancels boats for days at a time.
Sea 23°C · 73°FHigh 32°C · 90°FRain 34 mm · 1.3 inVis 25 m · 82 ft
Cape Greco & Ayia Napa
Cyprus
Diving is possible year-round; May to October brings the warmest water and greater marine-life abundance.
Water 17–28°C · 63–82°F
Capo Caccia & Nereo Cave
Italy
May–Oct is the settled season; winter mistral and north-westerlies make the exposed cape unworkable for weeks at a time.
Sea 24°C · 75°FHigh 30°C · 86°FRain 13 mm · 0.5 inVis 30 m · 100 ft
Capo Carbonara
Italy
May–Oct is the settled season with the warmest water; the mistral and easterlies close the exposed seccas in winter.
Sea 26°C · 79°FHigh 31°C · 88°FRain 87 mm · 3.4 inVis 40 m · 130 ft
Capri
Italy
June to September is the peak, with warm water and every site in reach; July and August are also the busiest months on the island.
Water 13–28°C · 55–82°F
Catania & the Cyclops Islands
Italy
Dived year-round; late summer and autumn add pelagics at Capo Molini, and winter water drops to about 14°C.
Sea 26°C · 79°FHigh 40°C · 104°FRain 5 mm · 0.2 in
Cavtat & Konavle
Croatia
Summer is the warm stretch, with the sea at 21 to 26 °C; January brings the coolest water of the year.
Water 14–26°C · 57–79°F
Ceuta
Spain
Boats run all year; the sea is coolest in February and March, near 16 °C, and warmest in July and August, near 23 °C.
Water 16–23°C · 61–73°F
Corfu
Greece
No operator publishes opening months; ratings follow seatemperature.info's Corfu monthlies (below 18°C Nov-Mar, 26.4°C peak in August), with April kept open on operators' own spring dive reports.
Sea 25°C · 77°FHigh 33°C · 91°FRain 12 mm · 0.5 inVis 25 m · 82 ft
Corsica — Ajaccio & Sagone
France
West-coast centres run roughly April to November; the sea is above 20 °C from June to October and averages under 14 °C in February.
Sea 25°C · 77°FHigh 34°C · 93°FRain 22 mm · 0.9 inVis 25 m · 82 ft
Corsica — Calvi & the Revellata
France
Corsica's dive season runs roughly May to October; July and August are the peak tourist months, so June and September give the same sites with fewer boats.
Sea 25°C · 77°FHigh 32°C · 90°FRain 12 mm · 0.5 inVis 25 m · 82 ft
Corsica — Lavezzi & Bonifacio
France
Operators run Apr–Oct with July and August warmest; the Bouches de Bonifacio funnel wind and can close the crossing at short notice.
Sea 25°C · 77°FHigh 32°C · 90°FRain 10 mm · 0.4 inVis 30 m · 100 ft
Costa Blanca — Calpe, Moraira & Jávea
Spain
Dived all year, but the water sits near 14 °C from January to March and the season is treated as starting in spring; peak-season boat traffic closes some cave surfacing.
Sea 26°C · 79°FHigh 31°C · 88°FRain 6 mm · 0.2 inVis 20 m · 66 ft
Costa Brava — Blanes, Lloret & Tossa
Spain
Water holds above 20 °C from June to October and tops out around 25–26 °C in August; winter dives run at 12–14 °C.
Sea 24°C · 75°FHigh 27°C · 81°FRain 53 mm · 2.1 inVis 20 m · 66 ft
Costa Brava — L'Escala & the Montgrí Coast
Spain
Water runs from about 13 °C in February to 25 °C in July and August; no L'Escala centre publishes closing months, and the tramuntana can keep boats in port in any month.
Sea 23°C · 73°FHigh 32°C · 90°FRain 42 mm · 1.7 inVis 15 m · 50 ft
Costa Brava — Palamós, Llafranc & Begur
Spain
Surface water sits near 13 °C from January to March and peaks around 25 °C in August; local guidance is 5 mm in July and August, 7 mm April to June and September to October, drysuit the rest.
Sea 23°C · 73°FHigh 32°C · 90°FRain 42 mm · 1.7 inVis 20 m · 66 ft
Costa Brava — Sant Feliu de Guíxols
Spain
Centres in Sant Feliu and Platja d'Aro dive all year; logged sightings peak July to September and the water sits at 13 °C from January to March.
Sea 24°C · 75°FHigh 32°C · 90°FRain 42 mm · 1.7 inVis 20 m · 66 ft
Côte d'Azur — Cannes & the Estérel
France
Water runs about 13°C in February and 25°C in August, and diving carries on year-round; the Théoule park's shore trail opens only from mid-June to mid-September.
Sea 25°C · 77°FHigh 33°C · 91°FRain 19 mm · 0.7 inVis 25 m · 82 ft
Crete
Greece
April to November is the season, warmest from July to September; the summer meltemi can blow out the exposed north-coast sites for a day or two at a time.
Sea 26°C · 79°FHigh 32°C · 90°FRain 4 mm · 0.2 inVis 30 m · 100 ft
Dubrovnik & the Elafiti Islands
Croatia
Diving runs year-round; summer is the most popular season, for its warmer water and calm sea.
Water 13–28°C · 55–82°F
Egadi Islands
Italy
June to September is the best stretch across the islands, and Marettimo's best period runs from May to October.
Water 14–26°C · 57–79°F
Elba & the Tuscan Archipelago
Italy
The season runs May–September with a warm October; the sea bottoms out near 14 °C in February–March, spring and autumn winds push boats to sheltered sites, and Pianosa's buoys open April–November.
Sea 26°C · 79°FHigh 29°C · 84°FRain 27 mm · 1.1 inVis 25 m · 82 ft
Golfe de Valinco — Propriano & Porto-Pollo
France
Both centres run April to November and close for the winter; the water is about 15 °C at the edges of that season and 25 °C at its height.
Sea 25°C · 77°FHigh 31°C · 88°FRain 10 mm · 0.4 inVis 35 m · 115 ft
Halkidiki — Sithonia
Greece
Boat trips and Try Scuba run April to October; courses are sold year-round, but the sea sits around 14 °C from January to March.
Sea 26°C · 79°FHigh 32°C · 90°FRain 22 mm · 0.9 inVis 25 m · 82 ft
Herceg Novi & the Luštica Blue Cave
Montenegro
Boats run all year, but May to October is the main season; winter dives are colder and visibility drops.
Water 14–26°C · 57–79°F
Ibiza & Formentera
Spain
Logged dives climb from April, peak in July and August and fall away through November; December to March activity is negligible on both islands.
Sea 26°C · 79°FHigh 30°C · 86°FRain 5 mm · 0.2 inVis 30 m · 100 ft
Ischia & Procida
Italy
May to October is the best stretch, with warmer water and generally good visibility; one Forio centre keeps diving through the winter.
Water 14–26°C · 57–79°F
Islas Columbretes
Spain
Operators run May–Oct; the three-hour crossing is impractical in winter and the reserve issues a capped number of daily permits.
Sea 26°C · 79°FHigh 28°C · 82°FRain 16 mm · 0.6 inVis 40 m · 130 ft
Istria — Rovinj & Pula
Croatia
The main season runs 1 May to 31 October; the sea passes 20°C from mid-June to September, and a few sites are diveable only outside the high season.
Sea 25°C · 77°FHigh 32°C · 90°FRain 61 mm · 2.4 inVis 20 m · 66 ft
Kalkan
Turkey
The sea warms abruptly in late May or early June and stays warm into November; winter water drops to about 16 °C.
Water 16–28°C · 61–82°FVis 30 m · 100 ft
Kaş
Turkey
Apr–Nov is the operating season with Jun–Oct warmest and calmest; most centres close over winter.
Sea 27°C · 81°FHigh 32°C · 90°FRain 2 mm · 0.1 inVis 40 m · 130 ft
Kemer & Tekirova
Turkey
Diving is best from late May to early September, when the water is at its warmest.
Water 17–29°C · 63–84°F
Kornati Islands
Croatia
The park licenses diving Apr–Oct, warmest Jul–Sep; the bura wind closes the exposed outer walls at short notice.
Sea 24°C · 75°FHigh 35°C · 95°FRain 44 mm · 1.7 inVis 25 m · 82 ft
Kvarner — Cres, Krk & Lošinj
Croatia
Peak season is May to September and conditions hold into October; from winter into early spring the bora churns the water and brings current, with the sea at 12–14 °C.
Sea 24°C · 75°FHigh 32°C · 90°FRain 69 mm · 2.7 inVis 25 m · 82 ft
Kyrenia (Girne)
Cyprus
Diving runs all year, but the main season runs April to the New Year; July to September have the warmest water.
Water 17–29°C · 63–84°F
La Herradura
Spain
Dived all year; December to March sits at 14-16 °C and winter storms cut visibility to 5-10 m for days, while spring and autumn hold the most consistent 15-25 m.
Sea 23°C · 73°FHigh 30°C · 86°FRain 1 mm · 0.0 inVis 15 m · 50 ft
Larnaca — Zenobia
Cyprus
Diveable year-round: Jun–Oct is warmest with water above 23°C; Dec–Feb runs 16–18°C with the clearest water and the quietest moorings.
Sea 27°C · 81°FHigh 36°C · 97°FRain 1 mm · 0.0 inVis 30 m · 100 ft
Mallorca — Alcúdia, Pollença & Cap de Formentor
Spain
May to October is the season, with boats out daily; the Alcúdia centre dives all year. Water peaks at 26°C in August and falls to 14–15°C in February and March; winter is wet and windy.
Sea 26°C · 79°FHigh 31°C · 88°FRain 18 mm · 0.7 inVis 25 m · 82 ft
Mallorca — Palma & the Southwest
Spain
One Santa Ponça centre runs daily April–October and weekends only Nov–Mar; May–Sep brings the calmest seas and warmest water, with leisure-boat traffic in the bays at the height of summer.
Sea 26°C · 79°FHigh 32°C · 90°FRain 9 mm · 0.4 inVis 25 m · 82 ft
Malta & Gozo
Malta
Jun–Sep is the main season, with the sea averaging 21–26 °C; it never drops below 14 °C, so diving carries on through the winter.
Sea 26°C · 79°FHigh 30°C · 86°FRain 3 mm · 0.1 inVis 40 m · 130 ft
Marmaris & İçmeler
Turkey
May to October is the best time to dive; in the cooler months the water drops to about 20°C (68°F).
Water 20–28°C · 68–82°F
Medes Islands
Spain
Jun–Sep brings the warmest water, calmest seas, and peak grouper and fish activity; most dive centers scale back Dec–Feb.
Sea 23°C · 73°FHigh 32°C · 90°FRain 42 mm · 1.7 inVis 20 m · 66 ft
Menorca
Spain
Menorca's tourist season runs May to October; June to September holds the warmest water, near 25–27°C in August, while February and March fall to about 12–14°C.
Sea 26°C · 79°FHigh 30°C · 86°FRain 13 mm · 0.5 inVis 30 m · 100 ft
Mljet National Park
Croatia
May to September is the best stretch, when the sea is at its warmest; by January it has cooled to about 14 °C.
Water 14–26°C · 57–79°F
Palavas-les-Flots, Carnon & Villeneuve-lès-Maguelone
France
Clubs dive year-round, but logged visibility sits near 2 m and the sea at 10-12 °C from January to March; one club runs seven days a week in July and August.
Sea 22°C · 72°FHigh 35°C · 95°FRain 26 mm · 1.0 inVis 15 m · 50 ft
Pantelleria
Italy
The sea feels quite warm from June to October and cool from December to May; dives can be booked all year.
Water 15–25°C · 59–77°F
Piran & Portorož
Slovenia
Diving runs all year, but winter dives are on demand; summer fills the Piran Punta reef with life and brings a thermocline that can cloud the wrecks.
Water 9–25°C · 48–77°F
Ponza & the Pontine Islands
Italy
Diving runs April to early November and all but stops December–February; water peaks around 26–27 °C in August and is down to 14–15°C in March–April. Naples ferries are summer-only.
Sea 26°C · 79°FHigh 28°C · 82°FRain 23 mm · 0.9 inVis 35 m · 115 ft
Port-Cros & Îles d'Hyères
France
Jun–Sep is the main season with the warmest water; mistral winds close the exposed wreck sites in any month.
Sea 24°C · 75°FHigh 30°C · 86°FRain 11 mm · 0.4 inVis 25 m · 82 ft
Porto Cesareo & the Nardò Coast
Italy
Dives run all year; the sea is warmest from July to September and feels cold in January and February.
Water 14–26°C · 57–79°F
Portofino Marine Reserve
Italy
May–Oct is the settled season; visibility is often best in late autumn, and winter storms close the exposed southern walls.
Sea 26°C · 79°FHigh 33°C · 91°FRain 44 mm · 1.7 inVis 20 m · 66 ft
Premuda
Croatia
Apr–Oct is the season with the clearest water in late summer; the bura closes the exposed offshore wreck at short notice.
Sea 25°C · 77°FHigh 30°C · 86°FRain 54 mm · 2.1 inVis 20 m · 66 ft
Primošten & Rogoznica
Croatia
The swimming season runs June to October; Pongo prices a low season as well, so winter diving happens at around 12–15 °C.
Sea 25°C · 77°FHigh 29°C · 84°FRain 43 mm · 1.7 inVis 25 m · 82 ft
Rhodes
Greece
May to October is the season, peaking July to September; centres still run in October, charter flights stop after October, and very little is dived from November to March.
Sea 26°C · 79°FHigh 36°C · 97°FRain 4 mm · 0.2 inVis 30 m · 100 ft
Samos
Greece
Diving runs from May to October; July to October brings the warmest water, while summer north winds raise waves on exposed coasts.
Water 16–25°C · 61–77°F
Santa Maria di Leuca
Italy
Early summer brings sunfish and July and August the warmest sea; February is the coldest month.
Water 14–26°C · 57–79°F
Santa Maria Navarrese & Arbatax
Italy
The Arbatax boats run from April to October; July to September has the warmest water of the year.
Water 14–25°C · 57–77°F
Santorini & the Caldera
Greece
Diving runs all year. April to November is the main season, with the calmest seas in summer; winter water averages about 16°C.
Water 16–27°C · 61–81°FVis 40 m · 130 ft
Sète & Frontignan
France
The sea averages about 12 °C in February against 22 °C in August and stays above 20 °C from June to October; cuttlefish return to the coast in April, and wind can close the exposed sites.
Sea 22°C · 72°FHigh 35°C · 95°FRain 26 mm · 1.0 in
Sozopol & St. Ivan Island
Bulgaria
June and July pair water that feels quite warm with the last of the seahorses; the sea stays quite warm into September and feels very cold from December to April.
Water 7–25°C · 45–77°F
Stintino & the Asinara National Park
Italy
June to September has the warmest water; July and August are also the busiest months on this coast.
Water 13–24°C · 55–75°F
Tabarca & Santa Pola
Spain
The sea averages 14 °C in February, the coldest month, and 26 °C in August, the warmest.
Water 14–26°C · 57–79°F
Tabarka
Tunisia
Winter swell hammers this exposed coast; May-October brings calm seas and the best visibility, with La Galite crossings only in settled summer weather.
Sea 26°C · 79°FHigh 38°C · 100°FRain 21 mm · 0.8 inVis 30 m · 100 ft
Taranto & the Gulf of Taranto
Italy
The sea feels quite warm from June to September and cold in January and February; October is mild.
Water 14–26°C · 57–79°F
Tarragona
Spain
Sea temperature falls below 14 °C from December to March and passes 24 °C from June to September, the practical shoulder of the local season.
Sea 26°C · 79°FHigh 31°C · 88°FRain 23 mm · 0.9 inVis 15 m · 50 ft
Tavolara & La Maddalena
Italy
April to October is the main season; summer brings the clearest water, while winter wind and current cut visibility.
Water 14–25°C · 57–77°F
Tremiti Islands
Italy
Operators run Apr–Oct with Jun–Sep warmest; winter bora and Adriatic swell close the ferry and the dive centres.
Sea 26°C · 79°FHigh 33°C · 91°FRain 37 mm · 1.5 inVis 35 m · 115 ft
Ustica
Italy
May–Oct brings the warmest water, around 18–26°C, and the best visibility; many dive centers close over winter.
Sea 27°C · 81°FHigh 30°C · 86°FRain 7 mm · 0.3 inVis 35 m · 115 ft
Varna & Cape Kaliakra
Bulgaria
The season runs April to November; June to September is the best stretch, with the sea near 24 °C.
Water 7–25°C · 45–77°F
Vela Luka & the Blue Hole
Croatia
Boats run from early May to mid-October; July to September has the warmest water, and most centres close after the summer.
Water 14–25°C · 57–77°F
Vis
Croatia
Diving runs May to October; the surface reaches 22–25 °C in July and August, and visibility is most reliable from late June to early October.
Sea 25°C · 77°FHigh 30°C · 86°FRain 31 mm · 1.2 inVis 25 m · 82 ft
Vlora, Karaburun & Sazan
Albania
Trips run all year, to Sazan as well as the peninsula; the sea is warmest from July to September and coolest in February.
Water 15–25°C · 59–77°FVis 20 m · 66 ft
Zakynthos
Greece
Dive centres run trips May to October; the warmest water and calmest conditions come in summer, and the sea stays above 20°C into November.
Sea 26°C · 79°FHigh 29°C · 84°FRain 11 mm · 0.4 inVis 25 m · 82 ft

Also good in July: Aeolian Islands — Lipari & Vulcano, Agistri & Poros, Amorgos, Beirut & Jounieh, Byblos, Amchit & Batroun, Cala Gonone & the Gulf of Orosei, Çeşme & Ildır, Datça & the Knidos Peninsula, Fethiye & Ölüdeniz, Gallipoli — Dardanelles Wrecks, Hvar & the Pakleni Islands, Kalymnos & Telendos, Kea Channel, Kefalonia & Ithaca, Kos & the Kefalos Peninsula, Kuşadası, Lampedusa & Linosa, Lastovo & the Lastovnjaci, Lefkada & Meganisi, Leros & Lakki, Lesbos, Limassol & the Three Stars Wreck, Marseille & the Calanques, Milos & Kimolos, Paphos & Coral Bay, Paros & Naxos, Polignano a Mare & Monopoli, Punta Campanella & the Sorrento Coast, San Vito Lo Capo & Scopello, Sarandë & Ksamil, Skopelos, Thassos, Zadar & Dugi Otok

Cold Water42 at their peak

Aran Islands
Ireland
The only dive centre opens from March to November and is shut in winter; summer, with the warmest water, is the best time to dive.
Water 10–16°C · 50–61°F
Bell Island & Conception Bay
Canada
The season runs Jun–Sep; icebergs are best in June, humpbacks arrive with the capelin in July, and winter shuts everything down.
Water 0–15°C · 32–59°FHigh 25°C · 77°FRain 95 mm · 3.7 inVis 30 m · 100 ft
Bohuslän & Gullmarsfjord
Sweden
Late winter gives the clearest water once the plankton dies back; Jul–Sep is warmest and easiest for shore entries.
Water 2–18°C · 36–64°FHigh 24°C · 75°FRain 78 mm · 3.1 inVis 20 m · 66 ft
Bornholm
Denmark
Jun–Sep is warmest and calmest; late winter gives the clearest water, and the Baltic can ice over in hard years.
Sea 18°C · 64°FHigh 22°C · 72°FRain 76 mm · 3.0 inVis 20 m · 66 ft
British Columbia — Browning Pass
Canada
Most operators run June through September for reliable weather and access; water is famously clearer in winter but few trips run then, and conditions turn harsh.
Sea 12°C · 54°FHigh 23°C · 73°FRain 76 mm · 3.0 inVis 20 m · 66 ft
Cornwall — Padstow & the Manacles
United Kingdom
Wrecks and reefs are dived all year when the weather allows; mid-May to September brings the sharks.
Water 8–19°C · 46–66°F
Dover & Folkestone Wrecks
United Kingdom
The dive season runs May to October; some charters sail all year, but the sea feels very cold in March.
Water 8–18°C · 46–64°F
Dublin Bay
Ireland
Club boats run from April to October; high summer brings the longest days and evening dives, while March has the coldest water.
Water 9–15°C · 48–59°F
Farne Islands
United Kingdom
Summer and early autumn combine workable North Sea weather with playful, non-breeding seals; late-autumn pupping season brings huge seal numbers but rougher seas and some beach access restrictions.
Sea 14°C · 57°FHigh 22°C · 72°FRain 88 mm · 3.5 inVis 15 m · 50 ft
Faroe Islands
Faroe Islands
May–Sep is the practical season; North Atlantic weather closes the islands for days at a time even in midsummer.
Sea 10°C · 50°FHigh 13°C · 55°FRain 80 mm · 3.1 inVis 30 m · 100 ft
Fehmarn
Germany
Boats run from May to September, and July and August are the peak, with wreck trips almost every day.
Water 2–18°C · 36–64°F
Gdańsk Bay & Gdynia
Poland
July and August bring the warmest water; January to March is painfully cold, down to about 2 °C in March.
Water 2–19°C · 36–66°F
Gulen & the Sognefjord
Norway
Diving runs all year: winter brings the clearest water and the helmet jellyfish, spring and summer the best conditions.
Water 6–22°C · 43–72°FVis 35 m · 115 ft
Gulf of Finland
Finland
Jun–Sep is the open-water season; ice diving runs Feb–Apr, and the gulf freezes hard enough most winters to stop boat access.
Water 1–18°C · 34–64°FHigh 24°C · 75°FRain 56 mm · 2.2 inVis 15 m · 50 ft
Isles of Scilly
United Kingdom
Weather keeps the season short: most charters run from May to September, and a summer storm can still interrupt a trip.
Water 9–19°C · 48–66°F
Kinsale & Old Head
Ireland
Spring and summer bring the migrants, the egg-guarding lumpsuckers and the hydroid bloom; the sea is coldest in January.
Water 9–18°C · 48–64°F
Klaipėda & Curonian Spit
Lithuania
July and August bring the warmest water; winter is the coldest stretch, with the sea averaging about 5 °C.
Water 1–20°C · 34–68°F
Kola Peninsula & the Barents Sea
Russia
The main season runs from late May to August, with club trips into September; newcomers do best in summer, when the water is a little warmer.
Water 2–11°C · 36–52°FVis 20 m · 66 ft
Kristiansund & the Atlantic Ocean Road
Norway
The Atlantic Ocean Road centre runs from early June to late September; the Kristiansund club boat goes out every Sunday all year.
Water 5–17°C · 41–63°F
Lake Constance
Germany
Diving runs all year; guided dives run from April to October, while December and January bring char and eels to the Parkhaus Post overhang.
Water 4–22°C · 39–72°F
Lake Shikotsu
Japan
Diving runs all year; late June to August is the top season, and January and February bring dives under the ice.
Water 1–20°C · 34–68°F
Lillebælt & Middelfart
Denmark
Shore sites are dived all year; May to September is the best season for the Old Lillebælt Bridge, and winter, with water near 3 °C (38 °F), brings nudibranchs to Søbadet.
Water 3–18°C · 37–64°F
Lofoten Islands
Norway
Boats run all year; mid-June brings fresh kelp, July and August the warmest water, and September to November is the wettest stretch.
Water 5–12°C · 41–54°F
Lundy Island
United Kingdom
May–Sep is the season, and even then the Bristol Channel's huge tidal range means diving is planned around slack water.
Sea 16°C · 61°FHigh 23°C · 73°FRain 77 mm · 3.0 inVis 20 m · 66 ft
Malin Head
Ireland
May–Sep only, and even then the charter runs on a handful of settled days; Atlantic swell closes the ground for weeks.
Sea 14°C · 57°FHigh 19°C · 66°FRain 105 mm · 4.1 inVis 30 m · 100 ft
Narvik
Norway
Jun–Sep is the main season with long daylight; winter diving happens but with polar night and heavy ice on the fjord edges.
Sea 12°C · 54°FHigh 22°C · 72°FRain 122 mm · 4.8 inVis 30 m · 100 ft
Plymouth Sound & HMS Scylla
United Kingdom
Diving runs all year when the wind allows; July to September brings the warmest water and the blue shark snorkel trips.
Water 8–19°C · 46–66°F
Reykjanes Peninsula — Garður & Flekkuvík
Iceland
Departures run all year; July and August bring the warmest water, about 11 °C against 6 °C in March.
Water 6–11°C · 43–52°F
Sakhalin & Moneron Island
Russia
Moneron boats run from mid-June to the end of September, and August brings the warmest water, around 22 °C.
Water 2–22°C · 36–72°F
Saltstraumen
Norway
The current itself runs year-round on the tide, but winter brings harsher weather and fewer daylight slack-water windows, so ratings favor the more reliable months.
Sea 12°C · 54°FHigh 21°C · 70°FRain 126 mm · 5.0 inVis 15 m · 50 ft
Shakotan Peninsula
Japan
Diving runs all year; July to September is the best season for fish and visibility, while the colder months bring the sea lions.
Water 4–22°C · 39–72°F
Shetland
United Kingdom
Shetland's liveaboard diving runs as a summer season, from June to August.
Water 7–15°C · 45–59°F
Silfra
Iceland
Water temperature and clarity stay constant year-round since Silfra is fed by filtered glacial groundwater; ratings track daylight hours and road access to Þingvellir, not underwater conditions.
Water 2–4°C · 36–39°FHigh 19°C · 66°FRain 88 mm · 3.5 inVis 80 m · 262 ft
Sinyavino Lake & Yantarny
Russia
May to September is the busy season; the bases stay open all year, with a dry suit needed in the cold months.
Water 2–19°C · 36–66°F
Sound of Mull
United Kingdom
Apr–Oct is the season; visibility is often best in early spring before the plankton bloom, and winter gales stop the charters.
Sea 13°C · 55°FHigh 21°C · 70°FRain 128 mm · 5.0 inVis 20 m · 66 ft
St Abbs & Eyemouth
United Kingdom
Apr–Oct is the season, with Jun–Sep giving the warmest water and calmest seas; winter northerlies make the coast unworkable.
Sea 14°C · 57°FHigh 19°C · 66°FRain 73 mm · 2.9 inVis 20 m · 66 ft
Strýtan
Iceland
The vent's flow is constant year-round; ratings mainly reflect daylight hours, fjord sea state, and overlap with Eyjafjörður's summer whale season.
Water 3–10°C · 37–50°FHigh 16°C · 61°FRain 96 mm · 3.8 inVis 20 m · 66 ft
Svalbard
Norway
Expedition ships operate Jun–Sep in the polar summer; outside that window the archipelago is dark, iced in and inaccessible.
Water -2–6°C · 28–43°FHigh 9°C · 48°FRain 62 mm · 2.4 inVis 25 m · 82 ft
Ushuaia & the Beagle Channel
Argentina
Diving runs all year; the clearest water comes in winter, when it is also coldest, while summer plankton cuts visibility.
Water 2–10°C · 36–50°FVis 20 m · 66 ft
Väderöarna
Sweden
Boats run all year; summer brings the warmest water, peaking in July and August, while winter is drysuit season.
Water 3–18°C · 37–64°F
Verzasca Valley
Switzerland
Jun–Sep only, once the spring snowmelt has dropped; heavy rain raises the flow fast and makes the river undivable.
Water 6–14°C · 43–57°FHigh 22°C · 72°FRain 173 mm · 6.8 inVis 50 m · 164 ft
Weymouth & Portland
United Kingdom
Sea temperature runs from about 7 °C in February to 17 °C in August; winter gales off the Atlantic rather than the cold are what stop the boats.
Sea 17°C · 63°FHigh 23°C · 73°FRain 54 mm · 2.1 in

Also good in July: Åland Islands, Anglesey, Baltimore & Cape Clear Island, Barkley Sound, Belgian North Sea — Nieuwpoort, Cape Ann & Stellwagen Bank, Capernwray & the Lake District, Chausey Islands & Granville, Comox Valley & Hornby Island, Discovery Passage & Campbell River, Donegal Coast — Downings, Tory & Arranmore, Feldberger Seenlandschaft, Gothenburg Archipelago, Gotland & Fårö, Haida Gwaii, Halifax & St Margaret's Bay, Hel Peninsula, Isle of Skye, Isles of Shoals, Juneau & Auke Bay, Karlskrona & the Blekinge Archipelago, Kilkee & the Clare Coast, Kinlochbervie & the North-West Highlands, Koster Islands & Kosterhavet, Kreidesee Hemmoor, Lake Bled & Lake Bohinj, Lake Vättern, Loch Fyne & Loch Long, Öland & the Kalmar Strait, Øresund & Isefjord, Pembrokeshire & Skomer, Puget Sound, San Juan Islands, Scapa Flow, Seward & Resurrection Bay, Sochi & Lazarevskoye, South Funen Archipelago, Stockholm Archipelago & Dalarö, Strangford Lough, Tollensesee & Neubrandenburg, Vladivostok & Peter the Great Bay, White Sea — Chupa Bay & Nilmoguba, Zeeland — Oosterschelde & Grevelingen

Coral Triangle32 at their peak

Alor
Indonesia
April–November dry season gives the most reliable liveaboard access and calmer crossings.
Sea 28°C · 82°FHigh 30°C · 86°FRain 21 mm · 0.8 inVis 30 m · 100 ft
Amed
Indonesia
June to September is Bali's dry season, with hardly any rain on the coast; December to March brings west-monsoon showers.
Water 26–30°C · 79–86°FVis 30 m · 100 ft
Ataúro Island
Timor-Leste
May–November dry season gives calmer crossings from Dili; December–April monsoon roughens seas.
Sea 28°C · 82°FHigh 29°C · 84°FRain 14 mm · 0.6 inVis 30 m · 100 ft
Bangka Island
Indonesia
Mar–Nov is the settled season with the calmest channels; the north-west monsoon from December to February brings wind and swell.
Sea 29°C · 84°FHigh 29°C · 84°FRain 159 mm · 6.3 inVis 30 m · 100 ft
Belitung
Indonesia
May to September brings calm seas and excellent visibility; October to March is the rainy season.
Water 27–29°C · 81–84°FVis 18 m · 60 ft
Biak & Padaido Islands
Indonesia
The dry season, May to September, brings calm seas for the crossings to the Padaido Islands; the wetter months are less certain.
Water 29–30°C · 84–86°F
Bunaken
Indonesia
May–October dry season gives the clearest water; some rain and runoff November–April.
Sea 29°C · 84°FHigh 29°C · 84°FRain 158 mm · 6.2 inVis 30 m · 100 ft
Cenderawasih Bay
Indonesia
Whale sharks feed at the bagans all year; most liveaboards visit from June to October, when rough weather around Raja Ampat pushes routes into the sheltered bay.
Sea 30°C · 86°FHigh 29°C · 84°FRain 219 mm · 8.6 inVis 30 m · 100 ft
Derawan & Sangalaki
Indonesia
April–October dry season gives the clearest water and most reliable manta encounters at Sangalaki.
Sea 29°C · 84°FHigh 29°C · 84°FRain 166 mm · 6.5 inVis 35 m · 115 ft
Gili Islands
Indonesia
Divable year-round; Apr–Nov brings the calmest crossings, and mola mola occasionally appear Aug–Oct on the deeper sites.
Sea 28°C · 82°FHigh 30°C · 86°FRain 24 mm · 0.9 inVis 25 m · 82 ft
Kepulauan Seribu (Thousand Islands)
Indonesia
Diving runs year-round; the April to October dry season is calmest and clearest, while November to March brings rain, stronger currents and lower visibility.
Water 28–30°C · 82–86°F
Kimbe Bay
Papua New Guinea
Diveable year-round; May–October dry season typically gives clearer water and calmer seas.
Sea 29°C · 84°FHigh 30°C · 86°FRain 179 mm · 7.0 inVis 35 m · 115 ft
Komodo
Indonesia
Liveaboards run all year: April is often rated the best month, July to September is the big-fish peak, and the rainy months bring the best visibility and the mantas.
Sea 28°C · 82°FHigh 29°C · 84°FRain 27 mm · 1.1 inVis 30 m · 100 ft
Kota Belud — Usukan Bay & Mayne Rock
Malaysia
Boats run all year when the weather allows; February to July is the best stretch, and from October to December rough seas can cancel trips.
Water 27–30°C · 81–86°F
Labuan & Brunei Wrecks
Brunei
Calm seas and better visibility run March to October, with April to July the best stretch; the wet season from November to February is rougher and murkier.
Sea 30°C · 86°FHigh 31°C · 88°FRain 272 mm · 10.7 inVis 20 m · 66 ft
Lembeh Strait
Indonesia
Diveable all year; July and August bring the most critters, October to December the clearest water, and January and February the roughest seas.
Sea 29°C · 84°FHigh 29°C · 84°FRain 158 mm · 6.2 inVis 20 m · 66 ft
Mabul & Kapalai
Malaysia
Diveable year-round with little seasonal variation; muck subjects are present in all months.
Sea 29°C · 84°FHigh 29°C · 84°FRain 200 mm · 7.9 inVis 20 m · 66 ft
Mantanani Islands
Malaysia
February to July is the best season; rough seas from October to December can cancel the crossing.
Water 27–30°C · 81–86°FVis 40 m · 130 ft
Maumere Bay
Indonesia
April to October is the calmest and clearest window; January to March brings rougher crossings, though the sheltered inner bay still dives.
Water 26–29°C · 79–84°FVis 30 m · 100 ft
Menjangan & West Bali
Indonesia
Divable all year thanks to the lee of Java; Apr–Nov is driest, and the wet season only affects surface conditions.
Sea 28°C · 82°FHigh 27°C · 81°FRain 69 mm · 2.7 inVis 25 m · 82 ft
Milne Bay
Papua New Guinea
May–November dry season gives calmer seas for liveaboard crossings; wetter December–April.
Sea 27°C · 81°FHigh 28°C · 82°FRain 137 mm · 5.4 inVis 25 m · 82 ft
Morotai
Indonesia
Calm dry-season water from March to November; rain from November to March, when mobulas also visit GaloGalo from February.
Water 28–30°C · 82–86°F
New Ireland & Kavieng
Papua New Guinea
The New Hanover trips run from May to October; rain from late December to March and North Pacific swell from November to April mark the rest of the year.
Water 29–32°C · 84–90°F
Nusa Penida
Indonesia
Mola mola are most likely from July to October, inside the coldest months; mantas stay all year and are likeliest from March to June.
Sea 28°C · 82°FHigh 28°C · 82°FRain 36 mm · 1.4 in
Padangbai & Candidasa
Indonesia
Diveable all year; mola mola are likeliest July to October, while the November to March wet season cuts visibility and makes the islets harder to dive.
Water 23–29°C · 73–84°FVis 30 m · 100 ft
Rabaul & Simpson Harbour
Papua New Guinea
May to October is the best stretch; December to March is the wettest, though only marginally wetter than the rest of the year.
Water 29–30°C · 84–86°F
Sangeang & Bima Bay
Indonesia
April to November is the season and June to October the peak; in January and February most liveaboard operators do not run.
Water 24–28°C · 75–82°FVis 25 m · 82 ft
Sangihe — Banua Wuhu
Indonesia
Mar–Sep is the settled window for the crossing north from Manado; the north-west monsoon closes the chain from December to February.
Sea 30°C · 86°FHigh 29°C · 84°FRain 203 mm · 8.0 inVis 35 m · 115 ft
Solomon Islands — Munda
Solomon Islands
April–November dry season is calmest; December–March brings cyclone risk and rougher seas.
Sea 29°C · 84°FHigh 29°C · 84°FRain 289 mm · 11.4 inVis 30 m · 100 ft
Sumbawa — Moyo, Satonda & Saleh Bay
Indonesia
Diving runs all year; April to November has the best conditions, and January to March can bring inclement weather.
Water 24–28°C · 75–82°F
Togian Islands
Indonesia
Mar–Sep is driest and calmest; the wet season from November to February brings rain and rougher inter-island crossings.
Sea 30°C · 86°FHigh 31°C · 88°FRain 177 mm · 7.0 inVis 35 m · 115 ft
Tulamben
Indonesia
Diveable all year. April to July and October to November give the calmest, clearest water; December to March is the rainy season, with more run-off and fewer divers.
Sea 28°C · 82°FHigh 28°C · 82°FRain 36 mm · 1.4 inVis 25 m · 82 ft

Also good in July: Apo Island, Belongas Bay & South Lombok, Camiguin, Dauin, Dili, Florida & Russell Islands, Gizo, Halmahera — Kusu & Sali Islands, Iron Bottom Sound, Krakatau & Sangiang Island, Malapascua, Marovo Lagoon, Moalboal, Pulau Aur & Pulau Dayang, Rote Island, Semporna Islands — Pom Pom, Mataking & Tun Sakaran, Siargao, Sibu & Tinggi Islands, Sipadan, Siquijor, Takabonerate & Selayar, Tufi, Wakatobi

Atlantic26 at their peak

Algarve — Ocean Revival
Portugal
May–Oct is the settled season with the clearest water; Atlantic swell and cold water shut most operations over winter.
Sea 19°C · 66°FHigh 29°C · 84°FRain 1 mm · 0.0 inVis 10 m · 33 ft
Azores — Flores & Corvo
Portugal
June to September is the best time to dive; the clearest water lasts into October, spring water turns green, and in winter the Corvo ferry sails only when the weather allows.
Water 16–23°C · 61–73°F
Azores — Pico & Faial
Portugal
Jun–Sep brings warm water, calmer Atlantic swell, and peak mobula and shark activity at the seamounts; winter storms shut down offshore boat trips.
Sea 22°C · 72°FHigh 24°C · 75°FRain 34 mm · 1.3 inVis 30 m · 100 ft
Azores — Santa Maria
Portugal
Boats run May to October; July to September is the peak at Ambrósio, and the offshore trips run regularly from June.
Water 17–25°C · 63–77°FVis 40 m · 130 ft
Azores — São Jorge & Graciosa
Portugal
June to September is the best time to dive; the clearest water runs from August into October, and in spring visibility drops to an average of 10–15 m.
Water 16–23°C · 61–73°F
Azores — São Miguel
Portugal
June to September is the settled season and August into October the clearest water; diving carries on through winter in a 7-10mm or dry suit when swell allows.
Sea 22°C · 72°FHigh 24°C · 75°FRain 19 mm · 0.7 inVis 25 m · 82 ft
Azores — Terceira
Portugal
June to September is the best time to dive; August to October has the clearest water, and spring nutrients turn it green.
Water 15–25°C · 59–77°F
Belle-Île-en-Mer & Quiberon
France
The Quiberon base dives from April to October; summer brings the warmest water and dolphins, and cuttlefish come at its end.
Water 9–19°C · 48–66°F
Berlengas & Peniche
Portugal
June to October is the high season; from December to February the Atlantic swell allows diving only on occasional calm days.
Sea 18°C · 64°FHigh 27°C · 81°FRain 5 mm · 0.2 inVis 25 m · 82 ft
Bermuda
Bermuda
May to October is the season, warmest July to September at 27–28°C; the water falls to about 19°C by March, and winter storms make diving the exception.
Sea 28°C · 82°FHigh 29°C · 84°FRain 70 mm · 2.8 inVis 45 m · 148 ft
Boa Vista
Cabo Verde
Boats run all year; loggerheads mate around the reef rocks Jun–Sep, and rougher winter seas can affect the diving.
Water 21–28°C · 70–82°F
El Cabrón — Gran Canaria
Spain
Year-round diving in 18–24°C water; summer and early autumn are calmest, while winter swell can make the shore entry unsafe.
Sea 22°C · 72°FHigh 25°C · 77°FRain 2 mm · 0.1 inVis 25 m · 82 ft
El Hierro
Spain
Diveable year-round with mild swings in temperature; Jun–Oct brings the calmest seas and warmest water.
Sea 23°C · 73°FHigh 25°C · 77°FRain 1 mm · 0.0 inVis 30 m · 100 ft
Fuerteventura
Spain
Divable in every month; water runs 18–23°C, coolest in late winter and warmest from August into October, and the desert climate keeps conditions mild.
Sea 22°C · 72°FHigh 25°C · 77°FRain 1 mm · 0.0 inVis 25 m · 82 ft
Huelva Coast — Isla Cristina & El Rompido
Spain
Diving runs all year; May to October brings the warmest water and the best visibility, and trips are cancelled when sea conditions do not allow them.
Water 16–22°C · 61–72°F
Île d'Oléron & the Pertuis d'Antioche
France
The season runs from spring to autumn; summer brings the warmest water, while spring often gives the better visibility.
Water 10–20°C · 50–68°F
Île de Groix & Lorient
France
Boats go out every morning in July and August; the island club's season runs from April to October.
Water 9–19°C · 48–66°F
Illas Cíes & Ría de Vigo
Spain
Jun–Sep is the practical season, when Atlantic swell drops and park access is easiest; winter storms close the islands to diving.
Sea 18°C · 64°FHigh 33°C · 91°FRain 17 mm · 0.7 inVis 20 m · 66 ft
La Graciosa & the Chinijo Archipelago
Spain
May to October brings the warmest water and the best visibility; the mild climate keeps any month a reasonable time to come.
Water 18–21°C · 64–70°F
Lanzarote & Museo Atlántico
Spain
Divable all year in 18–24°C water; Jun–Oct is warmest and calmest, and angel sharks are most reliably seen Nov–Mar.
Sea 22°C · 72°FHigh 25°C · 77°FRain 1 mm · 0.0 inVis 25 m · 82 ft
Madeira
Portugal
Jun–Sep brings the warmest water and best odds of manta rays around the Desertas; diving continues year-round but cooler and rougher in winter.
Sea 23°C · 73°FHigh 25°C · 77°FRain 5 mm · 0.2 inVis 25 m · 82 ft
Porto Santo
Portugal
Diving runs all year. July to October holds the warmest water, logged at 22–23°C, February logs the lowest visibility, and the island's rain falls in winter.
Sea 22°C · 72°FHigh 23°C · 73°FRain 2 mm · 0.1 inVis 30 m · 100 ft
San Sebastián & Getaria
Spain
Getaria boats sail Tuesday to Sunday from June to September and only at weekends from October to May; August has the warmest water.
Water 13–21°C · 55–70°F
Santander & Isla de Mouro
Spain
Boats run from late April to late October; April to September is the best stretch, and visibility can pass 15 m in spring and summer.
Water 11–23°C · 52–73°F
São Vicente & Mindelo
Cabo Verde
Diving runs all year; July to November is the high season, and August to October is the rainy season, though little rain falls.
Water 20–27°C · 68–81°FVis 30 m · 100 ft
Tenerife
Spain
Divable all year in 18–25°C water; Jun–Oct is warmest and calmest, and winter swell mainly affects the north coast.
Sea 22°C · 72°FHigh 27°C · 81°FRain 1 mm · 0.0 inVis 25 m · 82 ft

Also good in July: Ascension Island, Cascais & Cabo Raso, Crozon Peninsula & the Iroise Marine Park, Dakar & Ngor, Gijón & Cabo Peñas, Glénan Archipelago, Gran Canaria — Las Palmas & the North Coast, La Palma, Sálvora, Ons & Ría de Arousa, Santo Antão, Sesimbra & the Arrábida, Tarifa & the Strait of Gibraltar

North America20 at their peak

Alger Underwater Preserve & Munising
United States
The diving season runs from mid-May to early October, and charters need booking in advance.
Water 1–17°C · 34–63°FVis 15 m · 50 ft
Blue Heron Bridge
United States
Divable year-round; Apr–Aug brings the warmest water and the widest range of juveniles, and every dive is tied to the high-tide window.
Sea 29°C · 84°FHigh 32°C · 90°FRain 173 mm · 6.8 inVis 20 m · 66 ft
Brockville — St. Lawrence
Canada
May–Oct is the season, with the clearest water in late autumn; the river ices over and charters stop entirely in winter.
Water 4–22°C · 39–72°FHigh 33°C · 91°FRain 80 mm · 3.1 inVis 10 m · 33 ft
Cabo Pulmo
Mexico
Warm water June-November brings bull sharks and large mobula aggregations; winter is cooler and calmer but still diveable.
Sea 29°C · 84°FHigh 33°C · 91°FRain 26 mm · 1.0 inVis 20 m · 66 ft
Catalina Island
United States
Jul–Oct brings the warmest water and best visibility as the kelp thins; winter storms cut visibility and cool it to 13°C.
Sea 21°C · 70°FHigh 26°C · 79°FRain 2 mm · 0.1 inVis 15 m · 50 ft
Ensenada & Punta Banda
Mexico
July to October brings the warmest water and the best visibility; November to March is cold and rough, and spring is cooler with active sea lions.
Water 11–24°C · 52–75°FVis 18 m · 60 ft
Florida Keys — Key Largo & Islamorada
United States
Winter cold fronts (December-February) bring choppier seas and cooler water; April-August offers the calmest conditions, though hurricane season runs June-November.
Sea 30°C · 86°FHigh 32°C · 90°FRain 167 mm · 6.6 inVis 20 m · 66 ft
Flower Garden Banks
United States
Charter season runs roughly April-October when Gulf seas are calmer; coral spawn a few nights after the August full moon, and winter cold fronts shut most operators down.
Sea 30°C · 86°FHigh 30°C · 86°FRain 125 mm · 4.9 inVis 40 m · 130 ft
Isle Royale
United States
The park is shut from November 1 to April 15; dive charters run in summer.
Water 1–13°C · 34–55°FVis 15 m · 50 ft
Key West
United States
Boats dive all year; May to October brings the warmest water and best visibility, but August to October is hurricane season.
Sea 30°C · 86°FHigh 31°C · 88°FRain 147 mm · 5.8 inVis 15 m · 50 ft
La Jolla Cove & Canyon
United States
Leopard sharks mass in the shallows Jul–Oct when visibility is also best; the market squid run peaks Nov–Mar on night dives.
Sea 21°C · 70°FHigh 28°C · 82°FRain 4 mm · 0.2 inVis 10 m · 33 ft
Lake Havasu
United States
March to September are the prime months on the lake; the water is coldest in January at about 13 °C and warmest in August at about 19 °C, and the lake is still dived on New Year's Day.
Water 13–19°C · 55–66°F
Lake Tahoe
United States
Prime months run July to September; shore access such as D.L. Bliss State Park closes to vehicles once snow sets in, and deep water stays near 4°C even at the height of summer.
Water 4–22°C · 39–72°FHigh 34°C · 93°FRain 8 mm · 0.3 inVis 20 m · 66 ft
Long Island Wreck Valley
United States
Offshore charters run roughly April through November, picking up from mid-June; winter Atlantic swell, cold and short daylight shut the fleet down from December to March.
Sea 20°C · 68°FHigh 27°C · 81°FRain 102 mm · 4.0 inVis 7 m · 23 ft
Loreto Bay National Park
Mexico
Mobula schools peak May to August, and summer brings the warmest, clearest water; winter north winds can keep boats in harbour.
Water 17–30°C · 63–86°F
Panama City Beach
United States
April to October is the main diving season; January and February bring water down to about 15 °C (59 °F).
Water 15–30°C · 59–86°F
Port Aransas & Corpus Christi
United States
Diving runs from late spring to late autumn and peaks in summer; winter and early spring rarely suit offshore trips, and sea conditions change from day to day.
Water 16–30°C · 61–86°F
Straits of Mackinac
United States
Charters run from mid-May and the season is June through September, with most preserve moorings in from late May to mid-September; early dives bring spawning whitefish and perch.
Water 4–20°C · 39–68°F
Thunder Bay — Alpena
United States
The season runs late May to early October, with July and August warmest; the lake is unworkably cold and rough otherwise.
Water 2–18°C · 36–64°FHigh 26°C · 79°FRain 78 mm · 3.1 inVis 30 m · 100 ft
Veracruz Reef System
Mexico
May–Aug is calmest and clearest; the nortes that blow from October to March regularly shut the port to small boats.
Sea 29°C · 84°FHigh 32°C · 90°FRain 252 mm · 9.9 inVis 20 m · 66 ft

Also good in July: Channel Islands, Fort Lauderdale, Laguna Beach, Dana Point & Newport Beach, Los Cabos, Marathon & the Middle Keys, Milwaukee & Port Washington, North Carolina Wrecks, North Florida Springs, Palm Beach & Jupiter, Penetanguishene & Southern Georgian Bay, Point Lobos, Puerto Vallarta & Banderas Bay, Rimouski & the Empress of Ireland, Tobermory — Fathom Five

East Asia18 at their peak

Amakusa
Japan
Diving runs all year; July coral spawning and the October cave season stand out, while winter brings drysuits and lumpsuckers, and north winds blow into spring.
Water 15–28°C · 59–82°F
Gangneung
South Korea
July to October is best; winter brings the clearest water, with 2 to 4 °C in January and February.
Water 2–21°C · 36–70°FVis 10 m · 33 ft
Izu Ōshima
Japan
Hammerhead schools run mid-June to mid-October; winter brings tropical strays and water as clear as Okinawa’s.
Water 16–28°C · 61–82°F
Jeju — Munseom
South Korea
Jun–Oct is warmest with the best visibility; winter drops to 14°C and typhoons can close the islets in late summer.
Sea 26°C · 79°FHigh 29°C · 84°FRain 230 mm · 9.1 inVis 25 m · 82 ft
Kerama Islands
Japan
Calmest seas and best clarity run April-September; winter brings choppier northeast winds and cooler water.
Sea 29°C · 84°FHigh 30°C · 86°FRain 146 mm · 5.7 inVis 30 m · 100 ft
Kozushima
Japan
July to September is the top season; strong west winds leave the sea unsettled from January to March.
Water 17–27°C · 63–81°FVis 30 m · 100 ft
Kushimoto
Japan
Jul–Oct is warmest with the widest range of tropical strays; winter drops to 16°C but gives the clearest water on the reef.
Sea 26°C · 79°FHigh 31°C · 88°FRain 263 mm · 10.4 inVis 25 m · 82 ft
Lanyu — Orchid Island
Taiwan
July to October brings stable seas; from November to March the north-east monsoon makes the east and north coasts rough.
Sea 30°C · 86°FHigh 31°C · 88°FRain 287 mm · 11.3 in
Mikomoto & Nakagi
Japan
The island's operator recommends June–October for hammerheads, when the sea is most settled; winter northerlies stop the boats, and swell cancels trips in any month.
Sea 25°C · 77°FHigh 28°C · 82°FRain 316 mm · 12.4 inVis 30 m · 100 ft
Miyakejima
Japan
June to October brings the warmest water, visibility up to 30 m and the two Megane-iwa openings; diving runs all year.
Water 17–29°C · 63–84°FVis 30 m · 100 ft
Muroto, Kannoura & Shishikui
Japan
May to July brings the bambooshark spawning; winter has steady visibility, but strong northwest wind can close sites.
Water 17–28°C · 63–82°FVis 13 m · 43 ft
Nanki-Shirahama & Tanabe
Japan
Diving runs all year; summer is the high season, with the warmest water and bays that face away from the south wind.
Water 17–28°C · 63–82°F
Ogasawara Islands
Japan
Calmest seas run April-October; humpback whales pass through December-April but winter crossings are rougher.
Sea 28°C · 82°FHigh 29°C · 84°FRain 101 mm · 4.0 inVis 35 m · 115 ft
Oki Islands
Japan
Summer brings calm straits and the clearest water; typhoons peak in September and October, and winter waves cancel ferries.
Water 11–28°C · 52–82°F
Pohang
South Korea
Most diving runs from June to October, and July and August are the warmest, most comfortable months.
Water 10–24°C · 50–75°FVis 15 m · 50 ft
Sokcho & Goseong
South Korea
July to October is the best stretch for East Sea diving; January and February bring water of 2 to 4 °C.
Water 2–21°C · 36–70°F
Tokunoshima
Japan
Calm seas open Tonbara from June to October, the water is warmest from July to October, May and June are the rainy season, and humpbacks come in winter.
Water 20–29°C · 68–84°FVis 30 m · 100 ft
Ulleungdo
South Korea
Jul–Oct is warmest and clearest; winter storms in the East Sea stop the ferry for days and close the season entirely.
Sea 24°C · 75°FHigh 27°C · 81°FRain 198 mm · 7.8 inVis 30 m · 100 ft

Also good in July: Amami Ōshima, Green Island, Hachijojima, Ishigaki, Izu Peninsula — Osezaki & IOP, Katsuura & Namegawa, Kenting, Kume Island, Miura Peninsula — Jogashima, Hayama & Zushi, Miyako-jima, Penghu Islands, Sado Island, Tateyama — Hazama, Nishikawana & Ito, Xiaoliuqiu

Pacific Islands18 at their peak

Beqa Lagoon
Fiji
Bull shark season runs May to September and tigers are likeliest June to August; in the November to April wet season, bad weather can cancel the shark dive.
Sea 26°C · 79°FHigh 27°C · 81°FRain 85 mm · 3.3 inVis 30 m · 100 ft
Bligh Water & Vatu-i-Ra
Fiji
Apr–Oct is the dry season with the best visibility; Nov–Mar is warmer but brings cyclone risk and rougher crossings.
Sea 26°C · 79°FHigh 28°C · 82°FRain 57 mm · 2.2 inVis 40 m · 130 ft
Bora Bora
French Polynesia
The dry May to October months are the high season, though the trade winds sometimes blow strongly; November to April is the wet season.
Water 26–31°C · 79–88°F
Fakarava
French Polynesia
Jun-Jul brings the grouper spawning aggregation and peak shark density; conditions stay clear and diveable year-round otherwise.
Sea 27°C · 81°FHigh 27°C · 81°FRain 46 mm · 1.8 inVis 40 m · 130 ft
Kadavu & the Great Astrolabe Reef
Fiji
Apr–Oct is the dry season with the best visibility; Nov–Mar brings cyclone risk and rain, though the water is warmest then.
Sea 26°C · 79°FHigh 26°C · 79°FRain 68 mm · 2.7 inVis 40 m · 130 ft
Kauaʻi — Poipu & the South Shore
United States
May to September brings the calmest seas and warmest water, though south-shore visibility tends to run a little better in winter.
Water 22–28°C · 72–82°FVis 30 m · 100 ft
Maui, Molokini & Lānaʻi
United States
April to October is the calm dry season; winter swells hit the north coast while south-facing sites stay open.
Sea 26°C · 79°FHigh 27°C · 81°FRain 45 mm · 1.8 inVis 30 m · 100 ft
Maupiti
French Polynesia
June to October pairs manta courtship with the clearest lagoon water, but the same months bring the mara'amu wind that can make outer-reef trips difficult.
Water 27–29°C · 81–84°F
Niue
Niue
Jul-Sep is peak season, combining calm seas with humpback whales; the Nov-Apr cyclone season brings more swell and rougher boat access.
Sea 26°C · 79°FHigh 27°C · 81°FRain 69 mm · 2.7 inVis 70 m · 230 ft
Oʻahu
United States
South-shore boat diving runs all year; the North Shore reefs at Pupukea are only calm from about May to October and are dangerous in winter.
Sea 26°C · 79°FHigh 29°C · 84°FRain 44 mm · 1.7 inVis 30 m · 100 ft
Port Vila & Efate
Vanuatu
Diving runs all year; July to September is the dry peak, and November to April brings cyclones, with some closures from mid-January to mid-March.
Water 24–30°C · 75–86°FVis 40 m · 130 ft
Rainbow Reef & Namena
Fiji
The May-Oct dry season gives the strongest coral color and clearest water; Nov-Apr brings warmer seas but cyclone risk and more rain.
Sea 27°C · 81°FHigh 29°C · 84°FRain 69 mm · 2.7 inVis 30 m · 100 ft
Rarotonga & Aitutaki
Cook Islands
Apr–Nov is the dry season with the clearest water and humpbacks Jul–Oct; Dec–Mar brings rain and cyclone risk.
Sea 25°C · 77°FHigh 26°C · 79°FRain 74 mm · 2.9 inVis 50 m · 164 ft
Rota
Northern Mariana Islands
Rota Hole is at its best from March to September for the light beams; the Shoun Maru is dived year-round.
Water 28–30°C · 82–86°F
Savai'i & Upolu
Samoa
May–Oct is the dry season with the calmest water and humpbacks Jul–Oct; Nov–Apr brings rain and cyclone risk.
Sea 28°C · 82°FHigh 29°C · 84°FRain 85 mm · 3.3 inVis 35 m · 115 ft
Tikehau
French Polynesia
Apr–Oct is drier with the calmest passes; the wet season from November to March brings rain and more wind but warm water.
Sea 27°C · 81°FHigh 28°C · 82°FRain 43 mm · 1.7 inVis 45 m · 148 ft
Vava'u
Tonga
Humpback season runs July to October; the wet season from November to April brings more rain.
Sea 26°C · 79°FHigh 27°C · 81°FRain 60 mm · 2.4 inVis 40 m · 130 ft
Yasawa Islands
Fiji
Mantas run from May to October, and June to August has the clearest and coolest water; the resort boats dive every day of the year.
Water 23–30°C · 73–86°FVis 40 m · 130 ft

Also good in July: Bikini Atoll, Espiritu Santo — SS Coolidge, Guam, Hilo, Huahine, Isle of Pines, Kona, Kosrae, Lifou, Majuro & Mili, Moorea, New Caledonia, Poindimié & Hienghène, Raiatea & Taha'a, Rangiroa, Savusavu & Natewa Bay, Tahiti & Teahupo'o, Tanna & Lenakel, Wallis Island (Uvea)

Australia & New Zealand14 at their peak

Exmouth Navy Pier
Australia
Divable year-round on slack water; Apr–Oct is the dry season and overlaps the wider Ningaloo whale shark and humpback seasons.
Sea 24°C · 75°FHigh 27°C · 81°FRain 12 mm · 0.5 inVis 20 m · 66 ft
Great Barrier Reef — Cairns & Ribbons
Australia
Boats sail all year; visibility peaks from September to November and corals spawn in October or November, while December to February brings the most rain, often at night.
Sea 25°C · 77°FHigh 25°C · 77°FRain 44 mm · 1.7 inVis 20 m · 66 ft
Jervis Bay
Australia
Apr–Jul is clearest as summer runoff clears; seals are present through winter and grey nurse numbers peak in the cooler months.
Sea 17°C · 63°FHigh 20°C · 68°FRain 74 mm · 2.9 inVis 30 m · 100 ft
Julian Rocks — Byron Bay
Australia
Leopard sharks arrive Dec–Apr and grey nurse Jun–Nov, so the site has a marquee species almost year-round.
Sea 21°C · 70°FHigh 22°C · 72°FRain 42 mm · 1.7 inVis 20 m · 66 ft
Lady Elliot Island
Australia
Mantas peak May–Aug when cooler water brings them in; humpbacks pass Jun–Oct and turtles nest Nov–Mar.
Sea 23°C · 73°FHigh 23°C · 73°FRain 39 mm · 1.5 inVis 25 m · 82 ft
Montague Island
Australia
Seal numbers peak May–Oct when the colony is fullest; summer brings warmer, clearer water from the East Australian Current.
Sea 17°C · 63°FHigh 18°C · 64°FRain 47 mm · 1.9 inVis 30 m · 100 ft
Mooloolaba
Australia
Grey nurse sharks hold at Nurse Rock July–October, the months operators also rate clearest; summer is murkier and falls inside the November–April cyclone season.
Sea 21°C · 70°FHigh 23°C · 73°FRain 46 mm · 1.8 inVis 20 m · 66 ft
Nelson Bay — Fly Point
Australia
Apr–Aug is clearest and coldest, with giant cuttlefish courting in winter; summer runoff can drop visibility to a few metres.
Sea 19°C · 66°FHigh 21°C · 70°FRain 56 mm · 2.2 inVis 15 m · 50 ft
Ningaloo Reef
Australia
Whale sharks aggregate mid-Mar–Jul after coral spawning; humpback whales pass close to the reef Jul–Oct; manta rays are present year-round.
Sea 24°C · 75°FHigh 26°C · 79°FRain 15 mm · 0.6 inVis 25 m · 82 ft
North Stradbroke Island — Point Lookout
Australia
Mantas work the Manta Bommie cleaning stations Oct–Apr; grey nurse sharks and humpbacks arrive Jun–Oct, when visibility is also at its best. Boats run Friday to Tuesday.
Sea 21°C · 70°FHigh 22°C · 72°FRain 47 mm · 1.9 inVis 20 m · 66 ft
NSW Central Coast
Australia
Logged visibility peaks May–Aug at 15 m or more, when the water is coldest at 16–17°C; spring is murkiest, with 5 m or less logged in October.
Sea 18°C · 64°FHigh 21°C · 70°FRain 51 mm · 2.0 inVis 20 m · 66 ft
Port Phillip — Portsea & Blairgowrie
Australia
The spider crab aggregation runs May–Jul; winter also brings the clearest water, while summer is warmest but greener.
Sea 12°C · 54°FHigh 15°C · 59°FRain 69 mm · 2.7 inVis 15 m · 50 ft
South West Rocks — Fish Rock
Australia
Grey nurse numbers peak Jun–Nov; the Eastern Australian Current brings the warmest, clearest water Jan–Apr.
Sea 20°C · 68°FHigh 21°C · 70°FRain 39 mm · 1.5 inVis 30 m · 100 ft
Whitsundays
Australia
May–Sep is dry with the best visibility; Nov–Mar is the wet season with cyclone risk and stinger suits required inshore.
Sea 23°C · 73°FHigh 24°C · 75°FRain 29 mm · 1.1 inVis 15 m · 50 ft

Also good in July: Mount Gambier — Limestone Coast, Osprey Reef, SS Yongala

Africa11 at their peak

Algoa Bay
South Africa
June and July bring the best visibility but also the coldest water; ragged-tooth sharks are in the Bay from November to May.
Sea 17°C · 63°FHigh 24°C · 75°FRain 35 mm · 1.4 inVis 20 m · 66 ft
Aliwal Shoal
South Africa
The reef is dived all year round; ragged-tooth sharks congregate from July to November, bull sharks gather from December to April.
Sea 22°C · 72°FHigh 27°C · 81°FRain 41 mm · 1.6 in
Bazaruto Archipelago
Mozambique
May–Oct is calmest with the best visibility; humpbacks pass Jul–Oct and whale sharks are most common Nov–Mar.
Sea 24°C · 75°FHigh 25°C · 77°FRain 32 mm · 1.3 inVis 30 m · 100 ft
Comoros — Mohéli
Comoros
Apr–Nov is the dry season with the best conditions and humpbacks Jul–Oct; Dec–Mar brings rain and cyclone risk.
Sea 26°C · 79°FHigh 26°C · 79°FRain 25 mm · 1.0 inVis 30 m · 100 ft
Durban
South Africa
March to July is best: low rainfall and south-westerlies bring clear water. Spring rain (September to December) clouds the water near the harbour and Umlaas canal mouths.
Water 21–26°C · 70–79°F
Lake Malawi
Malawi
May to October is the dry, settled stretch; the rains run from November to April and are heaviest from December to March.
Water 22–29°C · 72–84°FHigh 27°C · 81°FRain 5 mm · 0.2 in
Ponta do Ouro
Mozambique
Resident dolphins are seen year-round; shark activity at Pinnacles and whale migration peak July-October.
Sea 23°C · 73°FHigh 25°C · 77°FRain 23 mm · 0.9 inVis 20 m · 66 ft
Protea Banks
South Africa
Scalloped hammerheads school October-March, with great hammerheads most likely around March-April; bull (Zambezi) sharks aggregate June-September; ragged-tooth sharks pass through in winter.
Sea 22°C · 72°FHigh 24°C · 75°FRain 48 mm · 1.9 inVis 30 m · 100 ft
São Tomé & Príncipe
São Tomé and Príncipe
Jun–Sep is the dry season with the calmest water and humpbacks present; the Mar–May rains cut visibility sharply.
Sea 26°C · 79°FHigh 26°C · 79°FRain 24 mm · 0.9 inVis 25 m · 82 ft
Sodwana Bay
South Africa
Conditions are good all year; ragged-tooth sharks peak in January and February, and the clearest water runs from April to September.
Sea 23°C · 73°FHigh 30°C · 86°FRain 22 mm · 0.9 in
Wild Coast Sardine Run
South Africa
Peak sardine migration runs June-July; some years the shoal is thin or absent, an inherent unpredictability of this wild event.
Sea 21°C · 70°FHigh 27°C · 81°FRain 45 mm · 1.8 inVis 20 m · 66 ft

Also good in July: Chinhoyi Caves, Diani Beach, Hermanus, Jangamo & Guinjata Bay, Kizimkazi & Menai Bay, Mafia Island, Mnemba Atoll — Zanzibar, Paje & Jambiani, Pemba Island, Robberg & Plettenberg Bay, Tofo, Wasini Island & Kisite-Mpunguti

Eastern Pacific8 at their peak

Bahía Solano
Colombia
Jul–Oct is humpback season and the main reason to come; this is one of the wettest coasts on earth, so visibility is never reliable.
Sea 28°C · 82°FHigh 29°C · 84°FRain 974 mm · 38.3 inVis 20 m · 66 ft
Bat Islands
Costa Rica
Bull sharks are most reliable May-Oct, peaking Jul-Aug; Dec-Apr's cooler Papagayo upwelling brings clearer but colder water and far fewer sightings.
Sea 28°C · 82°FHigh 30°C · 86°FRain 167 mm · 6.6 inVis 20 m · 66 ft
Cocos Island
Costa Rica
June to October brings the hammerhead schools; December to May is the dry season, with calmer seas and clearer water.
Sea 28°C · 82°FHigh 28°C · 82°FRain 328 mm · 12.9 inVis 30 m · 100 ft
Galápagos — Darwin & Wolf
Ecuador
Whale sharks pass from June to November; the sea is calmer, warmer and clearer from December to May.
Sea 25°C · 77°FHigh 25°C · 77°FRain 15 mm · 0.6 inVis 25 m · 82 ft
Gorgona Island
Colombia
Jul–Oct is humpback season and the main reason to visit; Feb–Apr generally brings the clearest water in a very wet climate.
Sea 28°C · 82°FHigh 28°C · 82°FRain 146 mm · 5.7 inVis 20 m · 66 ft
Isla de la Plata
Ecuador
Jun–Oct combines the oceanic manta season with humpback whales; Jan–Apr is warmer and clearer but the big animals are largely absent.
Sea 25°C · 77°FHigh 24°C · 75°FRain 4 mm · 0.2 inVis 20 m · 66 ft
Malpelo
Colombia
Jan-Apr is cooler and drier with a shallow, cold thermocline; May-Dec runs warmer with better visibility and the strongest shark and pelagic activity.
Sea 27°C · 81°FHigh 27°C · 81°FRain 177 mm · 7.0 inVis 30 m · 100 ft
Nuquí & the Gulf of Tribugá
Colombia
Boats run all year; March to August is the best stretch, taking in the sardine run around May and the start of whale watching in July.
Water 25–30°C · 77–86°F

Also good in July: Coiba, Galápagos — Central & South Islands, Gulf of Chiriquí, Isla del Caño

Indian Ocean7 at their peak

Addu Atoll
Maldives
Addu's resident dive centre rates January to April driest and busiest and July to September best for visibility; May-June and October-December are wetter. Full and new moon run the strongest currents.
Sea 30°C · 86°FHigh 30°C · 86°FRain 167 mm · 6.6 inVis 35 m · 115 ft
Baa Atoll & Hanifaru Bay
Maldives
The Hanifaru aggregation runs May–Nov on the south-west monsoon and peaks Aug–Oct; Dec–Apr is calmer and clearer but the mantas disperse.
Sea 29°C · 84°FHigh 29°C · 84°FRain 172 mm · 6.8 inVis 30 m · 100 ft
Kish Island
Iran
Clear, sunny spring and summer are best; stormy autumn and late-winter seas stop the diving on rough days.
Water 22–34°C · 72–93°F
Mayotte
France
Dry season (May-Oct) brings calm seas and the clearest water, coinciding with the Jul-Sep humpback whale season; the wet season (Nov-Apr) raises cyclone risk.
Sea 26°C · 79°FHigh 27°C · 81°FRain 15 mm · 0.6 inVis 25 m · 82 ft
Réunion
France
May–Oct is the dry season with the calmest water and humpbacks Jul–Oct; Jan–Mar is cyclone season.
Sea 24°C · 75°FHigh 26°C · 79°FRain 12 mm · 0.5 inVis 30 m · 100 ft
Rodrigues
Mauritius
May–Jul and Oct–Nov are the calmest windows; Jan–Mar brings cyclone risk and August can be windy.
Sea 25°C · 77°FHigh 25°C · 77°FRain 16 mm · 0.6 inVis 40 m · 130 ft
Trincomalee & Kalpitiya
Sri Lanka
Trincomalee dives Apr–Sep; Kalpitiya's whale season runs Nov–Apr on the opposite monsoon, so one coast is always workable.
Sea 29°C · 84°FHigh 34°C · 93°FRain 37 mm · 1.5 inVis 30 m · 100 ft

Also good in July: Ari & Rasdhoo Atolls, Christmas Island, Cocos (Keeling) Islands, Fuvahmulah, Ifaty & Mangily, Mauritius, Nosy Be, Raa Atoll, Vaavu Atoll

Southeast Asia7 at their peak

Cham Islands & Hoi An
Vietnam
Boats run February to mid-October; June to August is the steadiest window, with 10–25 m visibility from mid-May to early September. Typhoons peak in September and October.
Water 24–29°C · 75–84°FVis 25 m · 82 ft
Côn Đảo
Vietnam
Northeast monsoon swell limits diving November-January; calmest seas and best visibility run June-August.
Sea 29°C · 84°FHigh 30°C · 86°FRain 231 mm · 9.1 inVis 20 m · 66 ft
Pattaya & the Sattahip Wrecks
Thailand
Gulf diving is best May-September and runs year-round; the wrecks are clearest November-March, though site charts drop to 1-2 m visibility in February, August, November and December.
Sea 30°C · 86°FHigh 31°C · 88°FRain 270 mm · 10.6 inVis 15 m · 50 ft
Quy Nhơn & Hòn Khô
Vietnam
March to September is the best window; October to February is the central coast's rainy season, when the sea can be rough and visibility poorer.
Water 22–31°C · 72–88°F
Redang & Perhentian Islands
Malaysia
The marine park is officially closed November 1-February 28 for the northeast monsoon; conditions are calmest and clearest April-September.
Sea 30°C · 86°FHigh 30°C · 86°FRain 173 mm · 6.8 inVis 20 m · 66 ft
Tioman
Malaysia
Northeast monsoon brings rough seas and closed resorts November-January; calmest conditions and best visibility run May-September.
Sea 29°C · 84°FHigh 30°C · 86°FRain 146 mm · 5.7 inVis 15 m · 50 ft
Whale Island & Van Phong Bay
Vietnam
Whale Island's dive season runs from mid-February to mid-October, and April to September are the best months for diving.
Water 25–29°C · 77–84°F

Also good in July: Koh Samui & Koh Phangan, Koh Tao, Kota Kinabalu & Tunku Abdul Rahman Park, Nha Trang, Pulau Hantu & Singapore's Southern Islands, Sail Rock — Hin Bai, Tenggol Island

Red Sea & Gulf of Aden6 at their peak

Aqaba
Jordan
Conditions stay calm and diveable year-round; water is coolest January–March.
Sea 27°C · 81°FHigh 41°C · 106°FRain 0 mm · 0.0 inVis 30 m · 100 ft
Brothers & Daedalus
Egypt
Boats run the offshore route from March to December; schooling hammerheads peak at Daedalus from June to August.
Sea 29°C · 84°FHigh 32°C · 90°FRain 0 mm · 0.0 inVis 30 m · 100 ft
Hamata & Wadi Lahami
Egypt
May to October is the calm window, with much less wind; diving runs all year, but sea state is wind-driven and can reroute a day.
Sea 30°C · 86°FHigh 38°C · 100°FRain 0 mm · 0.0 inVis 30 m · 100 ft
Hurghada & El Gouna
Egypt
Diving runs all year; the seas settle from March to November and are calmest in summer, while February brings the coolest water.
Sea 28°C · 82°FHigh 40°C · 104°FRain 0 mm · 0.0 in
Sharm El Sheikh — Ras Mohammed
Egypt
Hammerhead sightings at Tiran peak June–September; winter winds can make Tiran crossings choppier.
Sea 29°C · 84°FHigh 34°C · 93°FRain 0 mm · 0.0 inVis 35 m · 115 ft
Yanbu & the Seven Reefs
Saudi Arabia
Liveaboards run the Seven Reefs as a summer itinerary; day boats from Yanbu run year-round.
Water 24–32°C · 75–90°FVis 50 m · 164 ft

Also good in July: Abu Nuhas & Gubal Strait, Dahab, Eilat, El Quseir, Marsa Alam & Port Ghalib, Nuweiba, Safaga, St John's Reefs

Caribbean5 at their peak

Isla Mujeres
Mexico
Whale sharks aggregate Jun–Sep, peaking in July and August; sailfish work baitballs Jan–Mar. Both are snorkel-only. Reef diving runs all year.
Sea 29°C · 84°FHigh 31°C · 88°FRain 79 mm · 3.1 inVis 30 m · 100 ft
Mahahual (Costa Maya)
Mexico
Diving runs all year. The sea is calmest from June to early September; on rough days the port closes and boats stay in.
Water 27–30°C · 81–86°FVis 30 m · 100 ft
Montserrat
Montserrat
Diving runs all year; June to November is the best window, while winter swells can make conditions hard for newer divers.
Water 26–29°C · 79–84°F
Roatán
Honduras
March to August is dry with the calmest seas; October to February is the rainy season, wettest in November and December.
Sea 29°C · 84°FHigh 29°C · 84°FRain 212 mm · 8.3 inVis 25 m · 82 ft
Santa Marta & Tayrona
Colombia
Jun–Oct is warmest and clearest; the Dec–Apr upwelling brings 20°C green water, good for life but poor for visibility.
Sea 27°C · 81°FHigh 29°C · 84°FRain 92 mm · 3.6 inVis 25 m · 82 ft

Also good in July: Ambergris Caye (San Pedro), Aruba, Bayahibe, Bonaire, Cayman Brac, Cozumel, Curaçao, Dominica, Grand Cayman, Guadeloupe — Cousteau Reserve, Los Roques, María la Gorda, Nassau & New Providence, Portobelo, Providencia & San Andrés, Riviera Maya Cenotes, RMS Rhone & Salt Island, Sint Maarten, St. Croix, St. Eustatius, Turks & Caicos, Utila, Virgin Gorda & the Dog Islands, Xcalak & Banco Chinchorro

South America3 at their peak

Arraial do Cabo
Brazil
Apr–Aug brings the calmest seas and clearest water; strong spring and summer winds regularly cancel boats, and upwelling drops temperatures sharply.
Sea 22°C · 72°FHigh 28°C · 82°FRain 27 mm · 1.1 inVis 30 m · 100 ft
Bonito
Brazil
The Apr–Sep dry season gives the most reliable clarity; heavy rain from Nov to Feb can cloud the rivers and close them for a day or two after storms.
Water 21–24°C · 70–75°FHigh 34°C · 93°FRain 27 mm · 1.1 inVis 50 m · 164 ft
Laje de Santos
Brazil
Autumn and winter (Mar–Sep) bring the clearest water and the manta ray aggregation; summer is warmer but rain and runoff cut visibility, and strong wind can close the park to boats.
Sea 21°C · 70°FHigh 25°C · 77°FRain 34 mm · 1.3 inVis 35 m · 115 ft

Also good in July: Abrolhos Archipelago, Ilha Grande & Angra dos Reis, Las Grutas, Máncora & Los Órganos, Mar del Plata, Paraty, Pucusana, Puerto Madryn & Península Valdés, Salvador & Baía de Todos os Santos

Water temperature in July

The measured sea surface in July (2011–2025 average) at every destination at its peak or in good shape, grouped by the suit our wetsuit guide recommends. Deeper water can run colder.at its peak