When to dive

Where to dive in September

296 dive destinations are at their peak in September, with another 247 in good shape. The strongest regions are Mediterranean, Cold Water, Coral Triangle; water runs from 0 °C to 32 °C (32–90 °F).

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At their peakGoodOther destinations

Warmest water: New Ireland & Kavieng29–32 °C (84–90 °F)
Clearest water: Silfra80 m (262 ft) visibility

Mediterranean97 at their peak

Agistri & Poros
Greece
May to October is the time to go; September and October bring the best conditions and the fewest crowds.
Water 15–26°C · 59–79°F
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 25°C · 77°FHigh 30°C · 86°FRain 60 mm · 2.4 inVis 40 m · 130 ft
Amorgos
Greece
Courses and testimonials cluster June to October, with October unpredictable. The meltemi unsettles late summer; winter winds and currents put some sites out of reach without closing the island.
Sea 24°C · 75°FHigh 29°C · 84°FRain 16 mm · 0.6 inVis 35 m · 115 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
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 21°C · 70°FHigh 29°C · 84°FRain 52 mm · 2.0 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 24°C · 75°FHigh 30°C · 86°FRain 41 mm · 1.6 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
Beirut & Jounieh
Lebanon
June to October is the reliable window, with September and October clearest; winter boats cancel often, and sand tigers are reported mostly in July and August.
Water 18–29°C · 64–84°F
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 24°C · 75°FHigh 27°C · 81°FRain 48 mm · 1.9 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 25°C · 77°FHigh 33°C · 91°FRain 19 mm · 0.7 inVis 35 m · 115 ft
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
Byblos, Amchit & Batroun
Lebanon
Visibility peaks from September to December as the sea settles; January to March bring the most weather cancellations.
Water 18–29°C · 64–84°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 32°C · 90°FRain 21 mm · 0.8 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 28°C · 82°FRain 37 mm · 1.5 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 31°C · 88°FRain 37 mm · 1.5 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 65 mm · 2.6 inVis 30 m · 100 ft
Cala Gonone & the Gulf of Orosei
Italy
Mid-May to the end of October is the main season; August brings the warmest water.
Water 14–27°C · 57–81°F
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 21°C · 70°FHigh 31°C · 88°FRain 53 mm · 2.1 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 22°C · 72°FHigh 29°C · 84°FRain 52 mm · 2.0 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 28°C · 82°FRain 42 mm · 1.7 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 25°C · 77°FHigh 29°C · 84°FRain 47 mm · 1.9 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 35°C · 95°FRain 45 mm · 1.8 in
Çeşme & Ildır
Turkey
Diving stops in January and February; September is among the best months, and the stingrays mate in October and November.
Water 15–23°C · 59–73°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 30°C · 86°FRain 66 mm · 2.6 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 24°C · 75°FHigh 30°C · 86°FRain 64 mm · 2.5 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 24°C · 75°FHigh 28°C · 82°FRain 33 mm · 1.3 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 24°C · 75°FHigh 28°C · 82°FRain 46 mm · 1.8 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 29°C · 84°FRain 58 mm · 2.3 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 26°C · 79°FRain 82 mm · 3.2 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 22°C · 72°FHigh 29°C · 84°FRain 63 mm · 2.5 inVis 15 m · 50 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 29°C · 84°FRain 63 mm · 2.5 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 24°C · 75°FHigh 29°C · 84°FRain 47 mm · 1.9 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 31°C · 88°FRain 18 mm · 0.7 inVis 30 m · 100 ft
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 24°C · 75°FHigh 27°C · 81°FRain 45 mm · 1.8 inVis 25 m · 82 ft
Fethiye & Ölüdeniz
Turkey
September and October pair warm sea with cooler air; winter brings heavy rain, strong winds and many closed facilities.
Water 16–30°C · 61–86°F
Gallipoli — Dardanelles Wrecks
Turkey
April–May and August–September bring the best conditions; the wrecks can be dived all year.
Sea 23°C · 73°FHigh 32°C · 90°FRain 24 mm · 0.9 in
Gökçeada
Turkey
September and October bring the calmest sea and the clearest water; the dive centres generally close from November to March.
Water 13–26°C · 55–79°F
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 24°C · 75°FHigh 28°C · 82°FRain 46 mm · 1.8 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 25°C · 77°FHigh 29°C · 84°FRain 48 mm · 1.9 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 28°C · 82°FRain 58 mm · 2.3 inVis 30 m · 100 ft
Ios & Folegandros
Greece
Seas are calmer from late spring to early autumn; the Meltemi wind can chop the sea in July and August, the warmest months.
Water 16–26°C · 61–79°F
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 69 mm · 2.7 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 24°C · 75°FHigh 28°C · 82°FRain 113 mm · 4.4 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 28°C · 82°FHigh 30°C · 86°FRain 18 mm · 0.7 inVis 40 m · 130 ft
Kea Channel
Greece
Expeditions run roughly May–October; the Aegean meltemi blows hardest in July–August and the strait closes over winter.
Sea 25°C · 77°FHigh 29°C · 84°FRain 24 mm · 0.9 inVis 25 m · 82 ft
Kefalonia & Ithaca
Greece
May–June and September–October bring the best visibility and smaller groups; August is the warmest month.
Water 15–26°C · 59–79°FVis 40 m · 130 ft
Kornati Islands
Croatia
The park licenses diving Apr–Oct, warmest Jul–Sep; the bura wind closes the exposed outer walls at short notice.
Sea 23°C · 73°FHigh 31°C · 88°FRain 119 mm · 4.7 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 22°C · 72°FHigh 28°C · 82°FRain 134 mm · 5.3 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 28°C · 82°FRain 24 mm · 0.9 inVis 15 m · 50 ft
Lampedusa & Linosa
Italy
August and September bring grey sharks to Lampione; ferry and flight options shrink in the off-season.
Water 15–26°C · 59–79°F
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 28°C · 82°FHigh 35°C · 95°FRain 4 mm · 0.2 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 29°C · 84°FRain 70 mm · 2.8 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 29°C · 84°FRain 61 mm · 2.4 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 29°C · 84°FRain 48 mm · 1.9 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 22°C · 72°FHigh 29°C · 84°FRain 63 mm · 2.5 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 28°C · 82°FRain 63 mm · 2.5 inVis 30 m · 100 ft
Milos & Kimolos
Greece
May, June, September and October give calm water with fewer crowds; the July and August meltemi can shut Kleftiko for days.
Water 16–26°C · 61–79°FVis 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 21°C · 70°FHigh 31°C · 88°FRain 53 mm · 2.1 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
Paros & Naxos
Greece
The Naxos centre opens mid-April to early November. The meltemi blows mid-May to mid-September, most constant in July and August, when boats keep to moorings sheltered from the north wind.
Sea 24°C · 75°FHigh 29°C · 84°FRain 17 mm · 0.7 inVis 25 m · 82 ft
Polignano a Mare & Monopoli
Italy
September is the pick, with the sea at 24–25 °C and the summer crowds gone; May and June are quiet too, and the water bottoms out near 14 °C in midwinter.
Water 14–26°C · 57–79°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 25°C · 77°FHigh 27°C · 81°FRain 72 mm · 2.8 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 23°C · 73°FHigh 28°C · 82°FRain 38 mm · 1.5 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 24°C · 75°FHigh 29°C · 84°FRain 62 mm · 2.4 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 24°C · 75°FHigh 27°C · 81°FRain 110 mm · 4.3 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 23°C · 73°FHigh 27°C · 81°FRain 118 mm · 4.6 inVis 25 m · 82 ft
Punta Campanella & the Sorrento Coast
Italy
Spring and autumn bring the most tuna and yellowtail to Li Galli; the sea warms from 14 °C (57 °F) in February to 26 °C (79 °F) in August.
Water 14–26°C · 57–79°F
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 27°C · 81°FHigh 33°C · 91°FRain 17 mm · 0.7 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 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
Sarandë & Ksamil
Albania
Diving runs all year with the right wetsuit; June and September pair warm water with fewer divers than July and August.
Water 15–26°C · 59–79°FVis 30 m · 100 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 21°C · 70°FHigh 31°C · 88°FRain 53 mm · 2.1 in
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
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 25°C · 77°FHigh 29°C · 84°FRain 54 mm · 2.1 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 24°C · 75°FHigh 30°C · 86°FRain 60 mm · 2.4 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 26°C · 79°FHigh 29°C · 84°FRain 46 mm · 1.8 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 24°C · 75°FHigh 27°C · 81°FRain 83 mm · 3.3 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 28°C · 82°FRain 72 mm · 2.8 inVis 25 m · 82 ft

Also good in September: Aeolian Islands — Lipari & Vulcano, Baia & the Phlegraean Fields, Budva & Jaz, Ceuta, Costa Brava — Palamós, Llafranc & Begur, Datça & the Knidos Peninsula, Dubrovnik & the Elafiti Islands, Filicudi & Salina, Hvar & the Pakleni Islands, Kalymnos & Telendos, Kemer & Tekirova, Kos & the Kefalos Peninsula, Kuşadası, Lastovo & the Lastovnjaci, Lefkada & Meganisi, Leros & Lakki, Lesbos, Limassol & the Three Stars Wreck, Marseille & the Calanques, Paphos & Coral Bay, Piran & Portorož, San Vito Lo Capo & Scopello, Santa Maria di Leuca, Skopelos, Sozopol & St. Ivan Island, Tabarka, Thassos, Zadar & Dugi Otok

Cold Water31 at their peak

Barkley Sound
Canada
Dived year-round; autumn is the prime window, winter brings the clearest water and June a plankton bloom near the surface.
Water 8–19°C · 46–66°FVis 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 20°C · 68°FRain 90 mm · 3.5 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 17°C · 63°FHigh 20°C · 68°FRain 58 mm · 2.3 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 11°C · 52°FHigh 23°C · 73°FRain 151 mm · 5.9 inVis 20 m · 66 ft
Chausey Islands & Granville
France
The ratings follow the sea temperature, warmest in August and September (about 18 °C) and coldest in February (about 9 °C); no month is singled out for diving.
Water 9–19°C · 48–66°F
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
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 13°C · 55°FHigh 20°C · 68°FRain 69 mm · 2.7 inVis 15 m · 50 ft
Halifax & St Margaret's Bay
Canada
Late August and September bring the warmest water and the odd seahorse; winter, free of rain runoff, brings clear water.
Water 1–17°C · 34–63°F
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
Kilkee & the Clare Coast
Ireland
The dive centre opens May to September; late August and September bring the warmest water and the triggerfish.
Water 10–16°C · 50–61°F
Kreidesee Hemmoor
Germany
Diveable year-round in a drysuit; semidry season runs April to November. Deep water stays near 5°C year-round; clarity depends more on weather and diver traffic than on the calendar.
Water 5–18°C · 41–64°FHigh 26°C · 79°FRain 57 mm · 2.2 inVis 40 m · 130 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
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
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 17°C · 63°FHigh 21°C · 70°FRain 98 mm · 3.9 inVis 20 m · 66 ft
Nanaimo & Gabriola Island
Canada
Clearest water runs September to March; spring and summer blooms cloud the surface layer.
Water 6–13°C · 43–55°F
Øresund & Isefjord
Denmark
Spring brings the best visibility on the Anemone Wreck, and September and October decent visibility and weather on Vapper; the Munkholm Bridge is dived through autumn and winter.
Water 2–18°C · 36–64°F
Oslofjord — Nesodden & Fornebu
Norway
Autumn and winter are usually the high season; September to March has the clearest water, April to October the warmest.
Water 3–18°C · 37–64°FVis 25 m · 82 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
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 16°C · 61°FRain 151 mm · 5.9 inVis 15 m · 50 ft
Scapa Flow
United Kingdom
Boats run from Easter to early November, and visibility improves in autumn once the plankton dies back.
Sea 13°C · 55°FHigh 17°C · 63°FRain 105 mm · 4.1 inVis 20 m · 66 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
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 13°C · 55°FRain 144 mm · 5.7 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
Skarnsundet & the Trondheim Fjord
Norway
Diving runs all year; September and October give the best odds of fine weather and clear water, while spring and summer plankton blooms can cut visibility.
Water 4–12°C · 39–54°FVis 15 m · 50 ft
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 14°C · 57°FHigh 18°C · 64°FRain 137 mm · 5.4 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 13°C · 55°FHigh 18°C · 64°FRain 61 mm · 2.4 inVis 20 m · 66 ft
Stockholm Archipelago & Dalarö
Sweden
Autumn, winter and spring are the best time for the Dalarö wrecks; a drysuit is needed in every season.
Water 1–19°C · 34–66°F
Vladivostok & Peter the Great Bay
Russia
In August and the first half of September the upper layer of the sea warms to a comfortable level; from December to April it is painfully cold, and some bays freeze in February.
Water 0–20°C · 32–68°FVis 20 m · 66 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 21°C · 70°FRain 70 mm · 2.8 in

Also good in September: Anglesey, Aran Islands, Attersee, Baltimore & Cape Clear Island, Belgian North Sea — Nieuwpoort, Bell Island & Conception Bay, Cape Ann & Stellwagen Bank, Capernwray & the Lake District, Comox Valley & Hornby Island, Discovery Passage & Campbell River, Donegal Coast — Downings, Tory & Arranmore, Dublin Bay, Faroe Islands, Fehmarn, Feldberger Seenlandschaft, Gdańsk Bay & Gdynia, Gothenburg Archipelago, Gotland & Fårö, Gulen & the Sognefjord, Gulf of Finland, Hel Peninsula, Horseshoe Bay & Howe Sound, Isle of Skye, Isles of Shoals, Kinlochbervie & the North-West Highlands, Klaipėda & Curonian Spit, Kola Peninsula & the Barents Sea, Koster Islands & Kosterhavet, Lago Nahuel Huapi & Bariloche, Lake Baikal — Listvyanka & Olkhon, Lake Bled & Lake Bohinj, Lake Shikotsu, Lake Vättern, Loch Fyne & Loch Long, Malin Head, Narvik, Öland & the Kalmar Strait, Pembrokeshire & Skomer, Puget Sound, Reykjanes Peninsula — Garður & Flekkuvík, Sakhalin & Moneron Island, San Juan Islands, Seward & Resurrection Bay, Sochi & Lazarevskoye, South Funen Archipelago, Stoney Cove, Strangford Lough, Strýtan, Svalbard, Tollensesee & Neubrandenburg, Ushuaia & the Beagle Channel, Väderöarna, Verzasca Valley, White Sea — Chupa Bay & Nilmoguba, Zeeland — Oosterschelde & Grevelingen

Coral Triangle28 at their peak

Alor
Indonesia
April–November dry season gives the most reliable liveaboard access and calmer crossings.
Sea 28°C · 82°FHigh 31°C · 88°FRain 11 mm · 0.4 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 30°C · 86°FRain 4 mm · 0.2 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 30°C · 86°FRain 104 mm · 4.1 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
Belongas Bay & South Lombok
Indonesia
Hammerheads peak from August to November; Belongas is calmest from March to mid-June and in October and November.
Water 25–30°C · 77–86°FVis 20 m · 66 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 30°C · 86°FRain 110 mm · 4.3 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 30°C · 86°FRain 181 mm · 7.1 inVis 30 m · 100 ft
Dili
Timor-Leste
The dry season runs from May to October and the rainy season from November to April; mid-September to November is the high season, when trip prices carry a surcharge.
Water 27–31°C · 81–88°F
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 32°C · 90°FRain 29 mm · 1.1 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 31°C · 88°FRain 148 mm · 5.8 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 27°C · 81°FHigh 30°C · 86°FRain 43 mm · 1.7 inVis 30 m · 100 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 28°C · 82°FHigh 30°C · 86°FRain 110 mm · 4.3 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 181 mm · 7.1 inVis 20 m · 66 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 29°C · 84°FRain 45 mm · 1.8 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 174 mm · 6.9 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 30°C · 86°FRain 38 mm · 1.5 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
Solomon Islands — Munda
Solomon Islands
April–November dry season is calmest; December–March brings cyclone risk and rougher seas.
Sea 29°C · 84°FHigh 30°C · 86°FRain 267 mm · 10.5 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
Wakatobi
Indonesia
Diveable all year; April–May and September–November are the peak months, and January and February the wettest.
Sea 28°C · 82°FHigh 28°C · 82°FRain 27 mm · 1.1 inVis 35 m · 115 ft

Also good in September: Ambon, Apo Island, Banda Islands, Dauin, Derawan & Sangalaki, Florida & Russell Islands, Gizo, Halmahera — Kusu & Sali Islands, Iron Bottom Sound, Kota Belud — Usukan Bay & Mayne Rock, Krakatau & Sangiang Island, Labuan & Brunei Wrecks, Malapascua, Mantanani Islands, Marovo Lagoon, Moalboal, Pulau Aur & Pulau Dayang, Rote Island, Sangihe — Banua Wuhu, Semporna Islands — Pom Pom, Mataking & Tun Sakaran, Siargao, Sibu & Tinggi Islands, Sipadan, Siquijor, Takabonerate & Selayar, Togian Islands, Tufi, Tulamben

Atlantic25 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 20°C · 68°FHigh 27°C · 81°FRain 20 mm · 0.8 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 23°C · 73°FHigh 25°C · 77°FRain 70 mm · 2.8 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 23°C · 73°FHigh 25°C · 77°FRain 48 mm · 1.9 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 19°C · 66°FHigh 26°C · 79°FRain 33 mm · 1.3 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 119 mm · 4.7 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 23°C · 73°FHigh 26°C · 79°FRain 12 mm · 0.5 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 24°C · 75°FHigh 26°C · 79°FRain 7 mm · 0.3 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 23°C · 73°FHigh 27°C · 81°FRain 5 mm · 0.2 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
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
La Palma
Spain
Diving runs year round; the south-coast centre rates September to November best, when the trade winds ease and the water is warmest. Dives and boat transits inside the marine reserve are capped.
Sea 24°C · 75°FHigh 26°C · 79°FRain 13 mm · 0.5 inVis 25 m · 82 ft
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 23°C · 73°FHigh 26°C · 79°FRain 7 mm · 0.3 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 24°C · 75°FHigh 26°C · 79°FRain 15 mm · 0.6 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 24°C · 75°FHigh 24°C · 75°FRain 10 mm · 0.4 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
Sesimbra & the Arrábida
Portugal
Aug–Oct is the warmest window; sheltered bay sites are diveable all year, but cape-facing sites take Atlantic swell in any month.
Sea 19°C · 66°FHigh 26°C · 79°FRain 25 mm · 1.0 inVis 15 m · 50 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 24°C · 75°FHigh 27°C · 81°FRain 7 mm · 0.3 inVis 25 m · 82 ft

Also good in September: Ascension Island, Cabo Verde — Sal, Cascais & Cabo Raso, Crozon Peninsula & the Iroise Marine Park, Dakar & Ngor, Gijón & Cabo Peñas, Glénan Archipelago, Gran Canaria — Las Palmas & the North Coast, Île d'Oléron & the Pertuis d'Antioche, Île de Groix & Lorient, Illas Cíes & Ría de Vigo, Sálvora, Ons & Ría de Arousa, Santo Antão, St Helena, Tarifa & the Strait of Gibraltar

Pacific Islands21 at their peak

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 29°C · 84°FRain 99 mm · 3.9 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
Huahine
French Polynesia
Humpback whales are counted from August to October; July and August are slightly drier, and the water stays warm all year.
Water 26–31°C · 79–88°F
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 25°C · 77°FHigh 26°C · 79°FRain 91 mm · 3.6 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 27°C · 81°FHigh 28°C · 82°FRain 50 mm · 2.0 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
Moorea
French Polynesia
Aug-Oct brings breeding humpback whales; the rest of the year stays warm with consistent reef and shark diving, aside from occasional Dec-Mar cyclone-season swell.
Sea 27°C · 81°FHigh 27°C · 81°FRain 55 mm · 2.2 inVis 30 m · 100 ft
New Caledonia
France
Sep–Dec is warmest and clearest before the wet season; Jan–Mar is cyclone season, and winter water drops to about 21°C.
Sea 23°C · 73°FHigh 24°C · 75°FRain 51 mm · 2.0 inVis 25 m · 82 ft
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 26°C · 79°FRain 77 mm · 3.0 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 27°C · 81°FHigh 29°C · 84°FRain 55 mm · 2.2 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
Raiatea & Taha'a
French Polynesia
Diving runs every day all year; humpback whales visit from September to early December and are met on snorkelling trips.
Water 26–31°C · 79–88°F
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 26°C · 79°FHigh 30°C · 86°FRain 115 mm · 4.5 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 25°C · 77°FRain 68 mm · 2.7 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 70 mm · 2.8 inVis 35 m · 115 ft
Tahiti & Teahupo'o
French Polynesia
August to October fall fully inside the humpback whale season; some centres swap dives for whale trips then, while others dive all year.
Water 26–29°C · 79–84°F
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 27°C · 81°FRain 42 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 63 mm · 2.5 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 September: Beqa Lagoon, Bikini Atoll, Espiritu Santo — SS Coolidge, Fakarava, Guam, Hilo, Isle of Pines, Kona, Kosrae, Lifou, Majuro & Mili, Nuku Hiva, Poindimié & Hienghène, Rangiroa, Rapa Nui (Easter Island), Savusavu & Natewa Bay, Tanna & Lenakel, Wallis Island (Uvea)

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
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 31°C · 88°FRain 62 mm · 2.4 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 30°C · 86°FHigh 33°C · 91°FRain 141 mm · 5.6 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 29°C · 84°FRain 5 mm · 0.2 inVis 15 m · 50 ft
Channel Islands
United States
Water is clearest and calmest September-November after summer plankton blooms settle; winter storms bring rough crossings and colder water.
Sea 19°C · 66°FHigh 25°C · 77°FRain 4 mm · 0.2 inVis 10 m · 33 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
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 147 mm · 5.8 inVis 40 m · 130 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 22°C · 72°FHigh 31°C · 88°FRain 8 mm · 0.3 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 31°C · 88°FRain 13 mm · 0.5 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 25°C · 77°FRain 99 mm · 3.9 inVis 7 m · 23 ft
Los Cabos
Mexico
Diving runs all year. August to February brings the best conditions and clearest autumn water; mobula rays pass from May to July.
Water 20–29°C · 68–84°FVis 30 m · 100 ft
Monterey Bay
United States
September to November is the calm, clearer stretch; summer plankton blooms cut visibility and winter brings the biggest swells.
Sea 15°C · 59°FHigh 28°C · 82°FRain 6 mm · 0.2 inVis 9 m · 30 ft
North Carolina Wrecks
United States
Charter season runs roughly April-November; sand tiger shark aggregations peak in September-October, while December-February seas are too rough for most boats.
Sea 27°C · 81°FHigh 29°C · 84°FRain 183 mm · 7.2 inVis 30 m · 100 ft
Palm Beach & Jupiter
United States
Lemon sharks aggregate Jan–Mar and goliath grouper spawn Aug–Sep; the Gulf Stream keeps visibility high year-round.
Sea 30°C · 86°FHigh 31°C · 88°FRain 218 mm · 8.6 inVis 30 m · 100 ft
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
Point Lobos
United States
Sep–Nov gives the clearest water after the summer plankton fades; winter storms close the reserve to diving for days at a time.
Sea 15°C · 59°FHigh 28°C · 82°FRain 6 mm · 0.2 inVis 20 m · 66 ft
San Diego — Wreck Alley, Point Loma & Coronado Islands
United States
Visibility is best from late summer into autumn and poorest from late winter through spring; lobster season runs October to March.
Water 8–14°C · 46–57°FVis 30 m · 100 ft
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 25°C · 77°FRain 58 mm · 2.3 inVis 30 m · 100 ft

Also good in September: Blue Heron Bridge, Florida Keys — Key Largo & Islamorada, Isle Royale, Magdalena Bay, Marathon & the Middle Keys, North Florida Springs, Penetanguishene & Southern Georgian Bay, Port Aransas & Corpus Christi, Puerto Vallarta & Banderas Bay, Rimouski & the Empress of Ireland, Sea of Cortez — La Paz, Tobermory — Fathom Five, Veracruz Reef System

East Asia13 at their peak

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
Izu Peninsula — Osezaki & IOP
Japan
Autumn brings the widest range of critters as tropical strays arrive on the Kuroshio; winter is coldest at 14°C but clearest.
Sea 27°C · 81°FHigh 30°C · 86°FRain 254 mm · 10.0 inVis 25 m · 82 ft
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 28°C · 82°FRain 214 mm · 8.4 inVis 25 m · 82 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 27°C · 81°FHigh 30°C · 86°FRain 300 mm · 11.8 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 29°C · 84°FHigh 30°C · 86°FRain 208 mm · 8.2 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 27°C · 81°FHigh 28°C · 82°FRain 295 mm · 11.6 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
Sado Island
Japan
Late August and September bring the warmest water and best visibility; winter monsoon winds chill the sea to 10°C or below by early spring.
Water 10–27°C · 50–81°FVis 20 m · 66 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 26°C · 79°FRain 161 mm · 6.3 inVis 30 m · 100 ft

Also good in September: Amakusa, Green Island, Hachijojima, Hong Kong — Sai Kung & Hoi Ha Wan, Ishigaki, Katsuura & Namegawa, Kenting, Kerama Islands, Kume Island, Miura Peninsula — Jogashima, Hayama & Zushi, Nanki-Shirahama & Tanabe, Ogasawara Islands, Penghu Islands, Pohang, Tateyama — Hazama, Nishikawana & Ito, Xiaoliuqiu

Australia & New Zealand12 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 23°C · 73°FHigh 33°C · 91°FRain 2 mm · 0.1 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 24 mm · 0.9 inVis 20 m · 66 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 25°C · 77°FRain 31 mm · 1.2 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 21 mm · 0.8 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 24°C · 75°FRain 40 mm · 1.6 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 27°C · 81°FRain 34 mm · 1.3 inVis 20 m · 66 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 23°C · 73°FHigh 29°C · 84°FRain 3 mm · 0.1 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 22°C · 72°FHigh 24°C · 75°FRain 32 mm · 1.3 inVis 20 m · 66 ft
Osprey Reef
Australia
Coral Sea crossings run in the calmer dry season; cyclone risk and rough seas suspend trips Jan–Feb, with hammerhead numbers building Sep–Dec.
Sea 26°C · 79°FHigh 26°C · 79°FRain 15 mm · 0.6 inVis 40 m · 130 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 25°C · 77°FRain 37 mm · 1.5 inVis 30 m · 100 ft
SS Yongala
Australia
August and September are the best months; from June to September the water cools to 22–25 °C.
Sea 24°C · 75°FHigh 29°C · 84°FRain 7 mm · 0.3 in
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 24°C · 75°FHigh 26°C · 79°FRain 8 mm · 0.3 inVis 15 m · 50 ft

Also good in September: Albany — King George Sound, Bay of Islands, Eaglehawk Neck, Fiordland, Goat Island — Leigh, Jervis Bay, Kaikōura, Lord Howe Island, Nelson Bay — Fly Point, Neptune Islands, Port Phillip — Portsea & Blairgowrie, Rapid Bay, Rowley Shoals

Red Sea & Gulf of Aden11 at their peak

Abu Nuhas & Gubal Strait
Egypt
Diving is year-round; Apr–Jun and Sep–Nov give the calmest seas, and winter northerlies can make the exposed north reef unworkable.
Sea 28°C · 82°FHigh 36°C · 97°FRain 0 mm · 0.0 inVis 30 m · 100 ft
Aqaba
Jordan
Conditions stay calm and diveable year-round; water is coolest January–March.
Sea 27°C · 81°FHigh 39°C · 102°FRain 4 mm · 0.2 inVis 30 m · 100 ft
Dahab
Egypt
Conditions stay calm and shore-diveable year-round; visibility peaks in spring and autumn shoulder months.
Sea 28°C · 82°FHigh 41°C · 106°FRain 0 mm · 0.0 inVis 30 m · 100 ft
Eilat
Israel
Divable all year; Mar–May and Sep–Nov are most comfortable, while July and August are extremely hot on the surface.
Sea 27°C · 81°FHigh 39°C · 102°FRain 4 mm · 0.2 inVis 25 m · 82 ft
El Quseir
Egypt
Sheltered shore dives, so the winter wind that disrupts boat schedules from October to April matters less; water falls to 23 °C by February and peaks near 30 °C in late summer.
Sea 29°C · 84°FHigh 37°C · 99°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 36°C · 97°FRain 0 mm · 0.0 inVis 30 m · 100 ft
Marsa Alam & Port Ghalib
Egypt
Diving runs all year; early autumn has the warmest sea without the August crowds.
Sea 29°C · 84°FHigh 36°C · 97°FRain 0 mm · 0.0 inVis 30 m · 100 ft
Nuweiba
Egypt
Diving runs all year; May-June and September-November are the best months, though July to October is very hot ashore.
Water 21–29°C · 70–84°FVis 30 m · 100 ft
Safaga
Egypt
Apr–Jun and Sep–Nov are the most comfortable windows; in every month the wind decides whether the offshore reefs can be reached.
Sea 29°C · 84°FHigh 43°C · 109°FRain 0 mm · 0.0 inVis 30 m · 100 ft
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 33°C · 91°FRain 0 mm · 0.0 inVis 35 m · 115 ft
St John's Reefs
Egypt
Mar–Jun and Sep–Nov are the settled windows; midsummer is very hot and winter northerlies make the long crossing uncomfortable.
Sea 30°C · 86°FHigh 37°C · 99°FRain 0 mm · 0.0 inVis 40 m · 130 ft

Also good in September: Brothers & Daedalus, Hurghada & El Gouna, Sudanese Red Sea, Yanbu & the Seven Reefs

Africa10 at their peak

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 21°C · 70°FHigh 33°C · 91°FRain 101 mm · 4.0 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 25°C · 77°FHigh 26°C · 79°FRain 8 mm · 0.3 inVis 30 m · 100 ft
Chinhoyi Caves
Zimbabwe
The pool stays a constant 22–24 °C all year; ratings track visibility, best in the Aug–Nov dry season and reduced when Dec–Mar rains cloud the entrance.
Water 22–24°C · 72–75°FHigh 37°C · 99°FRain 2 mm · 0.1 inVis 50 m · 164 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 27°C · 81°FRain 13 mm · 0.5 inVis 30 m · 100 ft
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 33°C · 91°FRain 1 mm · 0.0 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 53 mm · 2.1 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 86 mm · 3.4 inVis 30 m · 100 ft
Robberg & Plettenberg Bay
South Africa
September and October are the best months; onshore south-easterlies churn the sea up in summer, while winter westerlies clear the water.
Water 18–21°C · 64–70°FVis 10 m · 33 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 27°C · 81°FRain 43 mm · 1.7 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 36°C · 97°FRain 58 mm · 2.3 in

Also good in September: Algoa Bay, Diani Beach, Hermanus, Jangamo & Guinjata Bay, Kizimkazi & Menai Bay, Mafia Island, Mnemba Atoll — Zanzibar, Paje & Jambiani, Pemba Island, Wasini Island & Kisite-Mpunguti, Watamu & Malindi

Eastern Pacific7 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 28°C · 82°FRain 834 mm · 32.8 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 27°C · 81°FRain 226 mm · 8.9 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 23 mm · 0.9 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 136 mm · 5.4 inVis 20 m · 66 ft
Gulf of Chiriquí
Panama
Dec–Apr is the dry season with the calmest crossings; Sep–Oct is rainier but overlaps the southern humpback migration.
Sea 29°C · 84°FHigh 30°C · 86°FRain 337 mm · 13.3 inVis 25 m · 82 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 24°C · 75°FHigh 23°C · 73°FRain 1 mm · 0.0 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 106 mm · 4.2 inVis 30 m · 100 ft

Also good in September: Bat Islands, Coiba, Galápagos — Central & South Islands, Isla del Caño, Nuquí & the Gulf of Tribugá

Indian Ocean6 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 29°C · 84°FHigh 29°C · 84°FRain 154 mm · 6.1 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 169 mm · 6.7 inVis 30 m · 100 ft
Daymaniyat Islands
Oman
Sep–May is the main season; whale sharks are most reliable Aug–Nov, and the islands close to landing May–Oct for turtle nesting.
Sea 31°C · 88°FHigh 34°C · 93°FRain 8 mm · 0.3 inVis 30 m · 100 ft
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 11 mm · 0.4 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 9 mm · 0.4 inVis 30 m · 100 ft
Seychelles — Inner Islands
Seychelles
Inter-monsoon periods (Mar-May, Oct-Nov) are calmest with the best visibility; whale sharks pass through the inner-island channels August through October.
Sea 27°C · 81°FHigh 28°C · 82°FRain 118 mm · 4.6 inVis 25 m · 82 ft

Also good in September: Ari & Rasdhoo Atolls, Cocos (Keeling) Islands, Fuvahmulah, Haa Alif & Haa Dhaalu Atolls, Ifaty & Mangily, Lhaviyani Atoll, Mauritius, Musandam, Nosy Be, Raa Atoll, Rodrigues, Trincomalee & Kalpitiya

Caribbean5 at their peak

Bocas del Toro
Panama
Dry, calmer spells run February-April and September-October, when visibility improves and swell drops enough for Tiger Rock; the rest of the year is wetter and windier.
Sea 29°C · 84°FHigh 29°C · 84°FRain 288 mm · 11.3 inVis 25 m · 82 ft
Little Corn Island & the Corn Islands
Nicaragua
Blowing Rock and the east-side sites need calm seas, which come in April and May and from mid August to mid October.
Water 26–30°C · 79–86°F
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
Portobelo
Panama
Diving runs all year; May and August to October are the best months, and the rainy August and September count among them.
Water 27–29°C · 81–84°F
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 29°C · 84°FHigh 30°C · 86°FRain 206 mm · 8.1 inVis 25 m · 82 ft

Also good in September: Aruba, Bonaire, Curaçao, Isla Mujeres, Los Roques, Mahahual (Costa Maya), Riviera Maya Cenotes, Roatán, Utila

South America5 at their peak

Abrolhos Archipelago
Brazil
Aug–Oct pairs peak humpback whale season with fair diving; visibility is clearest and warmest Dec–Mar, while Apr–Jul river runoff lowers it to around 10 m.
Sea 25°C · 77°FHigh 25°C · 77°FRain 41 mm · 1.6 inVis 30 m · 100 ft
Fernando de Noronha
Brazil
Aug–Oct is peak dry season with the clearest water (up to 50 m); Feb–Jul brings rain and swell that reduce visibility, though diving continues year-round.
Sea 27°C · 81°FHigh 27°C · 81°FRain 13 mm · 0.5 inVis 45 m · 148 ft
Mar del Plata
Argentina
The best months are September to November and March to May. Water falls to 8–16 °C from May to September, though club boats still go out in July.
Water 8–23°C · 46–73°FVis 10 m · 33 ft
Puerto Madryn & Península Valdés
Argentina
Sea lion dives run best Sep–Mar when the colony is busiest; right whales are present Jun–Dec, and winter water drops to about 9°C.
Sea 11°C · 52°FHigh 22°C · 72°FRain 18 mm · 0.7 inVis 15 m · 50 ft
Recife Wrecks
Brazil
Sep–Mar is the dry season with the calmest seas and best visibility; Apr–Jul rain and runoff can drop it below 8 m.
Sea 27°C · 81°FHigh 30°C · 86°FRain 52 mm · 2.0 inVis 25 m · 82 ft

Also good in September: Arraial do Cabo, Arvoredo Marine Reserve, Bonito, Búzios, Ilha Grande & Angra dos Reis, Laje de Santos, Las Grutas, Máncora & Los Órganos, Paraty, Pucusana, Salvador & Baía de Todos os Santos, Ubatuba

Southeast Asia5 at their peak

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 29°C · 84°FHigh 30°C · 86°FRain 319 mm · 12.6 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
Sail Rock — Hin Bai
Thailand
The Gulf runs opposite to the Andaman coast: Mar–Sep is best, and the north-east monsoon closes it from November into January.
Sea 29°C · 84°FHigh 30°C · 86°FRain 269 mm · 10.6 inVis 20 m · 66 ft
Tenggol Island
Malaysia
August and September bring calm water and the whale shark run together; the island is closed to visitors through the monsoon.
Sea 29°C · 84°FHigh 30°C · 86°FRain 202 mm · 8.0 in
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 September: Côn Đảo, Koh Tao, Kota Kinabalu & Tunku Abdul Rahman Park, Nha Trang, Pulau Hantu & Singapore's Southern Islands, Pulau Weh, Redang & Perhentian Islands, Tioman

Water temperature in September

The measured sea surface in September (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