Where to dive in August

Mediterranean94 at their peak

1. 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

2. 

   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

3. 

   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 27°C · 81°FHigh 31°C · 88°FRain 26 mm · 1.0 inVis 40 m · 130 ft

4. 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

5. 

   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

6. 

   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 23°C · 73°FHigh 33°C · 91°FRain 28 mm · 1.1 inVis 15 m · 50 ft

7. 

   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

8. 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

9. 

   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 26°C · 79°FHigh 31°C · 88°FRain 36 mm · 1.4 inVis 20 m · 66 ft

10. 

    Bodrum

    Turkey

    Apr–Oct is the operating season with Jun–Sep warmest; the meltemi can blow hard through midsummer afternoons.

    Sea 27°C · 81°FHigh 36°C · 97°FRain 3 mm · 0.1 inVis 35 m · 115 ft

11. 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

12. 

    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

13. 

    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 26°C · 79°FHigh 35°C · 95°FRain 6 mm · 0.2 inVis 25 m · 82 ft

14. 

    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 27°C · 81°FHigh 30°C · 86°FRain 13 mm · 0.5 inVis 20 m · 66 ft

15. 

    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 27°C · 81°FHigh 35°C · 95°FRain 11 mm · 0.4 inVis 20 m · 66 ft

16. 

    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 27°C · 81°FHigh 29°C · 84°FRain 22 mm · 0.9 inVis 30 m · 100 ft

17. 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

18. 

    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 23°C · 73°FHigh 36°C · 97°FRain 27 mm · 1.1 in

19. 

    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 33°C · 91°FRain 28 mm · 1.1 inVis 25 m · 82 ft

20. 

    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

21. 

    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 25°C · 77°FHigh 31°C · 88°FRain 18 mm · 0.7 inVis 30 m · 100 ft

22. 

    Capo Carbonara

    Italy

    May–Oct is the settled season with the warmest water; the mistral and easterlies close the exposed seccas in winter.

    Sea 27°C · 81°FHigh 31°C · 88°FRain 18 mm · 0.7 inVis 40 m · 130 ft

23. 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

24. 

    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 27°C · 81°FHigh 39°C · 102°FRain 14 mm · 0.6 in

25. 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

26. 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

27. 

    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 26°C · 79°FHigh 34°C · 93°FRain 21 mm · 0.8 inVis 25 m · 82 ft

28. 

    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 26°C · 79°FHigh 34°C · 93°FRain 14 mm · 0.6 inVis 25 m · 82 ft

29. 

    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 26°C · 79°FHigh 32°C · 90°FRain 13 mm · 0.5 inVis 25 m · 82 ft

30. 

    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 26°C · 79°FHigh 32°C · 90°FRain 13 mm · 0.5 inVis 30 m · 100 ft

31. 

    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 27°C · 81°FHigh 32°C · 90°FRain 19 mm · 0.7 inVis 20 m · 66 ft

32. 

    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 26°C · 79°FHigh 28°C · 82°FRain 48 mm · 1.9 inVis 20 m · 66 ft

33. 

    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 24°C · 75°FHigh 33°C · 91°FRain 35 mm · 1.4 inVis 15 m · 50 ft

34. 

    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 24°C · 75°FHigh 33°C · 91°FRain 35 mm · 1.4 inVis 20 m · 66 ft

35. 

    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 25°C · 77°FHigh 33°C · 91°FRain 35 mm · 1.4 inVis 20 m · 66 ft

36. 

    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 26°C · 79°FHigh 33°C · 91°FRain 25 mm · 1.0 inVis 25 m · 82 ft

37. 

    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 27°C · 81°FHigh 31°C · 88°FRain 6 mm · 0.2 inVis 30 m · 100 ft

38. 

    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

39. 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

40. 

    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 31 mm · 1.2 inVis 25 m · 82 ft

41. 

    Gallipoli — Dardanelles Wrecks

    Turkey

    April–May and August–September bring the best conditions; the wrecks can be dived all year.

    Sea 25°C · 77°FHigh 34°C · 93°FRain 9 mm · 0.4 in

42. 

    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 32°C · 90°FRain 12 mm · 0.5 inVis 35 m · 115 ft

43. 

    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 27°C · 81°FHigh 32°C · 90°FRain 21 mm · 0.8 inVis 25 m · 82 ft

44. 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

45. 

    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 27°C · 81°FHigh 31°C · 88°FRain 23 mm · 0.9 inVis 30 m · 100 ft

46. 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

47. 

    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 27°C · 81°FHigh 29°C · 84°FRain 31 mm · 1.2 inVis 40 m · 130 ft

48. 

    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 26°C · 79°FHigh 33°C · 91°FRain 68 mm · 2.7 inVis 20 m · 66 ft

49. 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

50. 

    Kaş

    Turkey

    Apr–Nov is the operating season with Jun–Oct warmest and calmest; most centres close over winter.

    Sea 29°C · 84°FHigh 31°C · 88°FRain 4 mm · 0.2 inVis 40 m · 130 ft

51. 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

52. 

    Kornati Islands

    Croatia

    The park licenses diving Apr–Oct, warmest Jul–Sep; the bura wind closes the exposed outer walls at short notice.

    Sea 25°C · 77°FHigh 36°C · 97°FRain 47 mm · 1.9 inVis 25 m · 82 ft

53. 

    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

54. 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

55. 

    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 25°C · 77°FHigh 31°C · 88°FRain 4 mm · 0.2 inVis 15 m · 50 ft

56. 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

57. 

    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 36°C · 97°FRain 1 mm · 0.0 inVis 30 m · 100 ft

58. 

    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 27°C · 81°FHigh 31°C · 88°FRain 39 mm · 1.5 inVis 25 m · 82 ft

59. 

    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 27°C · 81°FHigh 32°C · 90°FRain 24 mm · 0.9 inVis 25 m · 82 ft

60. 

    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 27°C · 81°FHigh 30°C · 86°FRain 15 mm · 0.6 inVis 40 m · 130 ft

61. 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

62. 

    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 24°C · 75°FHigh 33°C · 91°FRain 35 mm · 1.4 inVis 20 m · 66 ft

63. 

    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 27°C · 81°FHigh 31°C · 88°FRain 31 mm · 1.2 inVis 30 m · 100 ft

64. 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

65. 

    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 23°C · 73°FHigh 36°C · 97°FRain 27 mm · 1.1 inVis 15 m · 50 ft

66. 

    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

67. 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

68. 

    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 27°C · 81°FHigh 29°C · 84°FRain 30 mm · 1.2 inVis 35 m · 115 ft

69. 

    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 25°C · 77°FHigh 31°C · 88°FRain 15 mm · 0.6 inVis 25 m · 82 ft

70. 

    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

71. 

    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 34°C · 93°FRain 59 mm · 2.3 inVis 20 m · 66 ft

72. 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 26°C · 79°FHigh 31°C · 88°FRain 51 mm · 2.0 inVis 20 m · 66 ft

73. 

    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 30°C · 86°FRain 54 mm · 2.1 inVis 25 m · 82 ft

74. 

    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 28°C · 82°FHigh 35°C · 95°FRain 6 mm · 0.2 inVis 30 m · 100 ft

75. 

    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

76. San Vito Lo Capo & Scopello

    Italy

    Summer is the peak season and conditions stay good well into autumn; the sea is warmest in August and coolest in February.

    Water 14–26°C · 57–79°F

77. 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

78. 

    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

79. 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

80. 

    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 23°C · 73°FHigh 36°C · 97°FRain 27 mm · 1.1 in

81. 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

82. 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

83. 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

84. 

    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 27°C · 81°FHigh 38°C · 100°FRain 20 mm · 0.8 inVis 30 m · 100 ft

85. 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

86. 

    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 27°C · 81°FHigh 32°C · 90°FRain 34 mm · 1.3 inVis 15 m · 50 ft

87. 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

88. 

    Tremiti Islands

    Italy

    Operators run Apr–Oct with Jun–Sep warmest; winter bora and Adriatic swell close the ferry and the dive centres.

    Sea 27°C · 81°FHigh 33°C · 91°FRain 36 mm · 1.4 inVis 35 m · 115 ft

89. 

    Ustica

    Italy

    May–Oct brings the warmest water, around 18–26°C, and the best visibility; many dive centers close over winter.

    Sea 28°C · 82°FHigh 31°C · 88°FRain 19 mm · 0.7 inVis 35 m · 115 ft

90. 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

91. 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

92. 

    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 26°C · 79°FHigh 30°C · 86°FRain 34 mm · 1.3 inVis 25 m · 82 ft

93. 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

94. 

    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 27°C · 81°FHigh 30°C · 86°FRain 15 mm · 0.6 inVis 25 m · 82 ft

Also good in August: Aeolian Islands — Lipari & Vulcano, Agistri & Poros, Amorgos, Beirut & Jounieh, Byblos, Amchit & Batroun, Çeşme & Ildır, Datça & the Knidos Peninsula, Fethiye & Ölüdeniz, Hvar & the Pakleni Islands, Kalymnos & Telendos, Kea Channel, Kefalonia & Ithaca, Kos & the Kefalos Peninsula, Kuşadası, 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, Sarandë & Ksamil, Skopelos, Thassos, Zadar & Dugi Otok

Cold Water47 at their peak

1. Åland Islands

   Finland

   Boats run from May to mid-September, with August the warmest month; nothing runs from October to April.

   Water 1–17°C · 34–63°F

2. 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

3. 

   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

4. 

   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 23°C · 73°FRain 89 mm · 3.5 inVis 20 m · 66 ft

5. 

   Bornholm

   Denmark

   Jun–Sep is warmest and calmest; late winter gives the clearest water, and the Baltic can ice over in hard years.

   Sea 19°C · 66°FHigh 23°C · 73°FRain 66 mm · 2.6 inVis 20 m · 66 ft

6. 

   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 24°C · 75°FRain 84 mm · 3.3 inVis 20 m · 66 ft

7. 

   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

8. 

   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

9. 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

10. 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

11. 

    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 21°C · 70°FRain 89 mm · 3.5 inVis 15 m · 50 ft

12. 

    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 89 mm · 3.5 inVis 30 m · 100 ft

13. 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

14. 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

15. 

    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 23°C · 73°FRain 77 mm · 3.0 inVis 15 m · 50 ft

16. 

    Haida Gwaii

    Canada

    Guided boat dives into the kelp run only in the summer months, and August has the warmest water.

    Water 6–12°C · 43–54°FVis 9 m · 30 ft

17. 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

18. 

    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

19. 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

20. 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

21. 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

22. 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

23. 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

24. 

    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

25. 

    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

26. 

    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

27. 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

28. 

    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 22°C · 72°FRain 95 mm · 3.7 inVis 20 m · 66 ft

29. 

    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 15°C · 59°FHigh 18°C · 64°FRain 116 mm · 4.6 inVis 30 m · 100 ft

30. 

    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 13°C · 55°FHigh 21°C · 70°FRain 121 mm · 4.8 inVis 30 m · 100 ft

31. 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

32. 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

33. 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

34. 

    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 13°C · 55°FHigh 20°C · 68°FRain 146 mm · 5.7 inVis 15 m · 50 ft

35. 

    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

36. 

    Shetland

    United Kingdom

    Shetland's liveaboard diving runs as a summer season, from June to August.

    Water 7–15°C · 45–59°F

37. 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 18°C · 64°FRain 97 mm · 3.8 inVis 80 m · 262 ft

38. 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

39. 

    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 20°C · 68°FRain 147 mm · 5.8 inVis 20 m · 66 ft

40. 

    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 83 mm · 3.3 inVis 20 m · 66 ft

41. 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 15°C · 59°FRain 100 mm · 3.9 inVis 20 m · 66 ft

42. 

    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 70 mm · 2.8 inVis 25 m · 82 ft

43. 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

44. 

    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

45. 

    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 23°C · 73°FRain 173 mm · 6.8 inVis 50 m · 164 ft

46. 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

47. 

    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 18°C · 64°FHigh 22°C · 72°FRain 71 mm · 2.8 in

Also good in August: Anglesey, Baltimore & Cape Clear Island, Barkley Sound, Belgian North Sea — Nieuwpoort, Cape Ann & Stellwagen Bank, Capernwray & the Lake District, Comox Valley & Hornby Island, Donegal Coast — Downings, Tory & Arranmore, Feldberger Seenlandschaft, Gothenburg Archipelago, Gotland & Fårö, Gulen & the Sognefjord, Hel Peninsula, Isle of Skye, Isles of Shoals, Juneau & Auke Bay, Karlskrona & the Blekinge Archipelago, 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, White Sea — Chupa Bay & Nilmoguba, Zeeland — Oosterschelde & Grevelingen

Coral Triangle28 at their peak

1. 

   Alor

   Indonesia

   April–November dry season gives the most reliable liveaboard access and calmer crossings.

   Sea 28°C · 82°FHigh 30°C · 86°FRain 9 mm · 0.4 inVis 30 m · 100 ft

2. 

   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

3. 

   Ataúro Island

   Timor-Leste

   May–November dry season gives calmer crossings from Dili; December–April monsoon roughens seas.

   Sea 27°C · 81°FHigh 30°C · 86°FRain 5 mm · 0.2 inVis 30 m · 100 ft

4. 

   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

5. 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

6. 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

7. 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

8. 

   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 105 mm · 4.1 inVis 30 m · 100 ft

9. 

   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 176 mm · 6.9 inVis 30 m · 100 ft

10. 

    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 31°C · 88°FRain 9 mm · 0.4 inVis 25 m · 82 ft

11. 

    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

12. 

    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 139 mm · 5.5 inVis 35 m · 115 ft

13. 

    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 17 mm · 0.7 inVis 30 m · 100 ft

14. 

    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 29°C · 84°FRain 105 mm · 4.1 inVis 20 m · 66 ft

15. 

    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 207 mm · 8.1 inVis 20 m · 66 ft

16. 

    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

17. 

    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 28°C · 82°FRain 36 mm · 1.4 inVis 25 m · 82 ft

18. 

    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 130 mm · 5.1 inVis 25 m · 82 ft

19. 

    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

20. 

    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

21. 

    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 29°C · 84°FRain 15 mm · 0.6 in

22. 

    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

23. 

    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

24. 

    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

25. 

    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 29°C · 84°FHigh 29°C · 84°FRain 121 mm · 4.8 inVis 35 m · 115 ft

26. 

    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 256 mm · 10.1 inVis 30 m · 100 ft

27. 

    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

28. 

    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 95 mm · 3.7 inVis 35 m · 115 ft

Also good in August: Apo Island, Camiguin, Dauin, Derawan & Sangalaki, Dili, 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, Semporna Islands — Pom Pom, Mataking & Tun Sakaran, Siargao, Siquijor, Takabonerate & Selayar, Tufi, Tulamben, Wakatobi

Atlantic27 at their peak

1. 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 29°C · 84°FRain 1 mm · 0.0 inVis 10 m · 33 ft

2. 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

3. 

   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 24°C · 75°FHigh 25°C · 77°FRain 51 mm · 2.0 inVis 30 m · 100 ft

4. 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

5. 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

6. 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 26 mm · 1.0 inVis 25 m · 82 ft

7. 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

8. 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

9. 

   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 27°C · 81°FRain 7 mm · 0.3 inVis 25 m · 82 ft

10. 

    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 29°C · 84°FHigh 29°C · 84°FRain 116 mm · 4.6 inVis 45 m · 148 ft

11. 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

12. 

    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 5 mm · 0.2 inVis 25 m · 82 ft

13. 

    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 26°C · 79°FRain 4 mm · 0.2 inVis 30 m · 100 ft

14. 

    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 27°C · 81°FRain 1 mm · 0.0 inVis 25 m · 82 ft

15. 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

16. 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

17. 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

18. 

    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 28 mm · 1.1 inVis 20 m · 66 ft

19. 

    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

20. 

    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 2 mm · 0.1 inVis 25 m · 82 ft

21. 

    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 9 mm · 0.4 inVis 25 m · 82 ft

22. 

    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 23°C · 73°FHigh 24°C · 75°FRain 4 mm · 0.2 inVis 30 m · 100 ft

23. 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

24. 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

25. 

    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

26. 

    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 27°C · 81°FRain 4 mm · 0.2 inVis 15 m · 50 ft

27. 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 23°C · 73°FHigh 27°C · 81°FRain 2 mm · 0.1 inVis 25 m · 82 ft

Also good in August: 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, Tarifa & the Strait of Gibraltar

North America22 at their peak

1. 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

2. 

   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 30°C · 86°FHigh 32°C · 90°FRain 185 mm · 7.3 inVis 20 m · 66 ft

3. 

   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 32°C · 90°FRain 86 mm · 3.4 inVis 10 m · 33 ft

4. 

   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 34°C · 93°FRain 89 mm · 3.5 inVis 20 m · 66 ft

5. 

   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 28°C · 82°FRain 5 mm · 0.2 inVis 15 m · 50 ft

6. 

   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

7. 

   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 31°C · 88°FHigh 32°C · 90°FRain 192 mm · 7.6 inVis 20 m · 66 ft

8. 

   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 31°C · 88°FRain 147 mm · 5.8 inVis 40 m · 130 ft

9. 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

10. 

    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 30°C · 86°FRain 7 mm · 0.3 inVis 10 m · 33 ft

11. 

    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

12. 

    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 33°C · 91°FRain 9 mm · 0.4 inVis 20 m · 66 ft

13. 

    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 21°C · 70°FHigh 27°C · 81°FRain 99 mm · 3.9 inVis 7 m · 23 ft

14. 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

15. 

    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

16. 

    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 32°C · 90°FRain 185 mm · 7.3 inVis 30 m · 100 ft

17. 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

18. 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

19. 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

20. 

    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

21. 

    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 75 mm · 3.0 inVis 30 m · 100 ft

22. 

    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 30°C · 86°FHigh 32°C · 90°FRain 286 mm · 11.3 inVis 20 m · 66 ft

Also good in August: Channel Islands, Fort Lauderdale, Marathon & the Middle Keys, Milwaukee & Port Washington, North Carolina Wrecks, North Florida Springs, Penetanguishene & Southern Georgian Bay, Point Lobos, Puerto Vallarta & Banderas Bay, Rimouski & the Empress of Ireland, Tobermory — Fathom Five

Pacific Islands20 at their peak

1. 

   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 87 mm · 3.4 inVis 30 m · 100 ft

2. 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 75 mm · 3.0 inVis 40 m · 130 ft

3. 

   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

4. 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

5. 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 81 mm · 3.2 inVis 40 m · 130 ft

6. 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

7. 

   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 56 mm · 2.2 inVis 30 m · 100 ft

8. 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

9. 

   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 58 mm · 2.3 inVis 30 m · 100 ft

10. 

    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 68 mm · 2.7 inVis 70 m · 230 ft

11. 

    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 49 mm · 1.9 inVis 30 m · 100 ft

12. 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

13. 

    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 29°C · 84°FRain 103 mm · 4.1 inVis 30 m · 100 ft

14. 

    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 63 mm · 2.5 inVis 50 m · 164 ft

15. 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

16. 

    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 69 mm · 2.7 inVis 35 m · 115 ft

17. 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

18. 

    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 37 mm · 1.5 inVis 45 m · 148 ft

19. 

    Vava'u

    Tonga

    Humpback season runs July to October; the wet season from November to April brings more rain.

    Sea 26°C · 79°FHigh 26°C · 79°FRain 64 mm · 2.5 inVis 40 m · 130 ft

20. 

    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 August: Bikini Atoll, Espiritu Santo — SS Coolidge, Fakarava, Guam, Hilo, Isle of Pines, Kona, Kosrae, Lifou, Majuro & Mili, New Caledonia, Poindimié & Hienghène, Raiatea & Taha'a, Rangiroa, Savusavu & Natewa Bay, Tanna & Lenakel, Wallis Island (Uvea)

East Asia17 at their peak

1. 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

2. 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

3. 

   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 28°C · 82°FHigh 30°C · 86°FRain 227 mm · 8.9 inVis 25 m · 82 ft

4. 

   Kerama Islands

   Japan

   Calmest seas and best clarity run April-September; winter brings choppier northeast winds and cooler water.

   Sea 29°C · 84°FHigh 31°C · 88°FRain 171 mm · 6.7 inVis 30 m · 100 ft

5. 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

6. 

   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 28°C · 82°FHigh 32°C · 90°FRain 222 mm · 8.7 inVis 25 m · 82 ft

7. 

   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 379 mm · 14.9 in

8. 

   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 29°C · 84°FRain 218 mm · 8.6 inVis 30 m · 100 ft

9. 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

10. 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

11. 

    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 147 mm · 5.8 inVis 35 m · 115 ft

12. 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

13. 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

14. 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

15. 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

16. 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

17. 

    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 26°C · 79°FHigh 29°C · 84°FRain 180 mm · 7.1 inVis 30 m · 100 ft

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

Australia & New Zealand13 at their peak

1. 

   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 30°C · 86°FRain 6 mm · 0.2 inVis 20 m · 66 ft

2. 

   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 22 mm · 0.9 inVis 20 m · 66 ft

3. 

   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 23°C · 73°FRain 49 mm · 1.9 inVis 20 m · 66 ft

4. 

   Lady Elliot Island

   Australia

   Mantas peak May–Aug when cooler water brings them in; humpbacks pass Jun–Oct and turtles nest Nov–Mar.

   Sea 22°C · 72°FHigh 23°C · 73°FRain 28 mm · 1.1 inVis 25 m · 82 ft

5. 

   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 20°C · 68°FRain 55 mm · 2.2 inVis 30 m · 100 ft

6. 

   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 20°C · 68°FHigh 24°C · 75°FRain 45 mm · 1.8 inVis 20 m · 66 ft

7. 

   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 18°C · 64°FHigh 24°C · 75°FRain 55 mm · 2.2 inVis 15 m · 50 ft

8. 

   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 27°C · 81°FRain 9 mm · 0.4 inVis 25 m · 82 ft

9. 

   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 23°C · 73°FRain 44 mm · 1.7 inVis 20 m · 66 ft

10. 

    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 23°C · 73°FRain 51 mm · 2.0 inVis 20 m · 66 ft

11. 

    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 23°C · 73°FRain 48 mm · 1.9 inVis 30 m · 100 ft

12. 

    SS Yongala

    Australia

    August and September are the best months; from June to September the water cools to 22–25 °C.

    Sea 23°C · 73°FHigh 27°C · 81°FRain 12 mm · 0.5 in

13. 

    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 25°C · 77°FRain 17 mm · 0.7 inVis 15 m · 50 ft

Also good in August: Jervis Bay, Mount Gambier — Limestone Coast, Osprey Reef, Port Phillip — Portsea & Blairgowrie

Africa9 at their peak

1. 

   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 31°C · 88°FRain 36 mm · 1.4 in

2. 

   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 12 mm · 0.5 inVis 30 m · 100 ft

3. 

   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 34°C · 93°FRain 1 mm · 0.0 inVis 50 m · 164 ft

4. 

   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 14 mm · 0.6 inVis 30 m · 100 ft

5. 

   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 30°C · 86°FRain 3 mm · 0.1 in

6. 

   Ponta do Ouro

   Mozambique

   Resident dolphins are seen year-round; shark activity at Pinnacles and whale migration peak July-October.

   Sea 22°C · 72°FHigh 24°C · 75°FRain 18 mm · 0.7 inVis 20 m · 66 ft

7. 

   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 21°C · 70°FHigh 25°C · 77°FRain 42 mm · 1.7 inVis 30 m · 100 ft

8. 

   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 22 mm · 0.9 inVis 25 m · 82 ft

9. 

   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 22°C · 72°FHigh 34°C · 93°FRain 18 mm · 0.7 in

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

Eastern Pacific8 at their peak

1. 

   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 827 mm · 32.6 inVis 20 m · 66 ft

2. 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 29°C · 84°FHigh 31°C · 88°FRain 213 mm · 8.4 inVis 20 m · 66 ft

3. 

   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 286 mm · 11.3 inVis 30 m · 100 ft

4. 

   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 14 mm · 0.6 inVis 25 m · 82 ft

5. 

   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 119 mm · 4.7 inVis 20 m · 66 ft

6. 

   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

7. 

   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 147 mm · 5.8 inVis 30 m · 100 ft

8. 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