Seasonal Calendar

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This is the place to find the best season at your favorite dive destinations. Listed in alphabetical order you’ll easily know where to go… and where not to! For the best time of the year to see your favorite marine animals


East Africa (Kenya and Tanzania)

The heavy rains occur between May and June, with short rains during November/December. The average temperatures range between 68°-90°F (20°C-32°C) typical equatorial climate. The right time for land packages with game viewing is a complicated affair; animal migrations are scheduled by rain, not calendars. The diving is simpler: September through March is when the winds should be favorable. Whale sharks often cruise the coast about February.


With no more than three degrees difference between summer and winter averages for air temperature, and very low annual rainfall, the main factor left to affect diving in Aruba is the wind. The trade winds blow year-round, but are highest from January through April. Bad weather on the coast of Venezuela can also cause a decrease in water visibility.


Yes, it’s reversed Down Under: Australia’s winter is during the Northern Hemisphere’s summer. That’s the easy part. From there, it gets increasingly complex; Australia’s diving areas are vast. Although the Great Barrier Reef gets most of the press, better by a hundred miles is the Coral Sea, whose outlying atolls and pinnacles such as Marion Reef offer some of the best diving in the world. Cyclone season is January through March; April, May, and June see heavy trade winds. The best season to dive Australia on a liveaboard (really the only way to see the best) is July through November. Best visibility at Osprey, in the northern Coral Sea, is between June and September. The other hot spots for Australian diving is clear across the continent on the remote west coast, and it’s famous for one reason: whale sharks congregate at Ningaloo Reef during March and April.


May through November is summer in the Bahamas. During these months, the most rain falls and temperatures average about 81°. Winter can bring surprisingly cool weather, with averages down about 70°. Northers can disrupt diving during winter months. The southern islands of the Bahamas chain usually manage to stay a degree or two warmer. Average time between hurricanes is nine years. Easterly trade winds predominate for most of the year, but there is usually a lee to be found for diving.

Baja (Mexico)

A one-word description of Sea of Cortez diving: variable. Water temperature and visibility varies dramatically. Two divers returning from the Baja only weeks apart can give such different reports that you have a difficult time believing they’ve been to the same destination. In the southern part of the Sea of Cortez, the temperature of the upper 30ft of water or so remains warm enough year-round (70° to 80s) to support tropicals and several varieties of hard coral. Below that depth, winter and spring water temperatures in the 50s and 60s freeze out the tropicals. From mid-summer through November, water temperature is 80°F or higher for as deep as sport divers would care to go. During spring and summer, the surface water temperature rises, of course, but the big change is the lowering of the thermocline. This is a complex and uneven process. During a June visit, the thermocline was at 45-50′. Sometimes the change was gradual or of small magnitude, but on one dive we recorded a plunge of 16 degrees between the surface, at 76°, and a thick layer of 60° planktonic green gloom 50 feet down. Later in the season, the water is 80° all the way past 100′. (We’ve even recorded 84° water in October.) Another seasonal variable is the plankton concentration. Sometimes the more plankton-rich waters can be observed as distinct layers and masses. Generally, our June visibility was 30-40′. Later in the summer, it’s usually 80-100′. After the first of December, north winds often make diving difficult because of rough seas. Sport diving effectively ceases until May. By spring the thermocline is high and a 1/4″ wetsuit is recommended (some sort of protection from jellyfish is recommended year-round). Tropical storms can occur during summer and fall, just as in the Caribbean. On average, they are most likely from mid-September to mid-October. La Paz and its waters tend to be protected from storm swells by a projection of land on the east and by large islands such as Isla Cerralvo. It’s almost always sunny, but during the winter, night air temperatures can drop down into the mid-fifties. Hottest months are August and September. Whale season is December to March.


The dry season runs from March through May. The most predictably good weather for diving is from April through June, when the winds are normally light. Hurricanes hit Belize an average of once every six years. Major hurricanes have hit in 1931, 1961, and 1978. During winter months (mainly December, January, and February), Belize is also subject to northers that blow down and disrupt diving for several days. Water temperature may dip as low as the 70s in the winter and reach as high as 85° in the summer.


Bonaire is a desert island, with a terrain and climate something like southern Arizona. Air temperatures are in the low to mid 70s at night, and the high 80s or low 90s during the day. But with the trade winds and moderate humidity, it rarely feels as hot as it is. Rainfall is usually scant, consisting of a few brief showers in the early morning, except during November and December, when occasionally it is overcast and rainy for a day or more. Total annual rainfall is about 20 inches, but every eight to ten years there’s a peak year, with total rainfall of two to three times the normal amount. 1988 was one such peak year, with the highest accumulations known since accurate record-keeping started over 200 years ago. Bonaire’s protected western coast offers almost ideal conditions 365 days a year – calm, warm, and clear water with gentle currents. The sky is usually dotted with puffy fair weather clouds that give a welcome respite from a tropical sun which can get quite intense, especially in May, June, and September. Winds are always from the east at a brisk 15-20 mph from January through August. They slow the last four months of the year, with occasional calm days that permit diving on the island’s exposed eastern coast. This is an experience not to be missed if the rare opportunity presents itself to see the huge sponges, gorgonia, coral heads and fish of the northern and eastern coasts. The water temperature in Bonaire ranges from 78 to 81 degrees. About three years out of every five, upwellings of cold, nutrient-rich water from the deep Atlantic spill into the Caribbean over the relatively shallow shelf that connects Trinidad with the Grenadines, and then it circulates westward to Bonaire. When this happens – usually during July – water temperature can drop into the low 70s and visibility everywhere can fall to 30ft or less. These conditions can last from one or two days to a week or more. Sometimes this cold upwelling water doesn’t come all the way to the surface but is only encountered at depth as a murky thermocline.

Borneo (Malaysia)

Sipadan is famous for its large population of green turtles. The turtles are there year-round, but the highest concentration is during the month of August (and there’s a whole lot of mating going on).The island is limestone and sand with no rivers, so runoff has little effect on water clarity. However, water clarity seems as unpredictable as the currents. Once, after I noticed heavy lightning off in the direction of the mainland, the water visibility dropped dramatically from 100ft to 50ft the next day, and heavy flotsam and debris floated in on the surface. But even then,some dives would have great visibility below 40ft, while other sites still had 100ft vis right below the surface. The ocean is roughest between November and February. The best season is between April and September, but diving is year-round.

Caribbean (in general)

Temperatures between summer and winter don’t normally vary much more than five degrees in the Caribbean. The average temperature is about 80° year-round. Naturally, southern islands tend to be a little warmer than the northern ones. For example, Curaçao’s southern location keeps its summer average at 83° and winter at 80°, while the northern Bahamas (Nassau) vary from a summer average of 81° down to a cool 69° average in the winter. There is a wet and dry season, with most rain falling between May/June and October/November. However, location and topography, such as rain shadows created by mountains, can play an important role in local weather conditions. Keep in mind that those cold fronts in the U.S. that dip down from the north can keep right on dipping to most of the northern islands, bringing cool temperatures and rough water in their wake.
Two other important factors to consider in the Caribbean are tourist season and hurricane season. The off-season for tourism is roughly mid-April to mid-December. It can mean much cheaper prices (up to 60% less) than in the busy high season. Although hurricanes can develop any time of the year, the season is generally considered to be from July to November, with September the most likely month. Island folklore has it this way: June, too soon. July, pass by. August, we must. Remember September. October, all over.


he Caymans’ hottest period is from May to November. During winter, temperatures can drop down to the low 70s. Rainy season starts in May and peaks in October. Rains are normally short and intense. Run-off has little effect on Grand Cayman’s water clarity, which averages about 135 feet horizontally on the deeper reefs. Both Little Cayman and Cayman Brac boast even higher visibility averages. Water temperatures vary, from the upper 70s in the winter to low 80s during the summer. Trade winds are out of the northeast in the winter and the southeast during the summer. Northwesterly storms can occur from December through April.

Cook Islands

These islands experience little fluctuation in climate and have moderate temperatures and humidity. It does rain, however, with the rainy season beginning in December and running through March. Water temperature varies from a mean of 81° in the summer (December being the middle of summer) to 78° during their winter (August being the middle of winter). Whale season is September and October. Hurricanes mainly develop from January to March, with the more severe ones hitting only about once every twenty years and lesser ones once every five years.

Cocos Island

Three hundred miles off Costa Rica’s shore, has a rainy season from June through December. Some records show that the sharks are seen more often during this rainy season. Diving is year-round, but some of the boats are pulled out of service from mid-September to October for repairs, indicating that this is probably not the best time to dive Cocos.


Cozumel enjoys a fairly constant temperature of 80°, but it rises into the 90s during July and August, which are also rainy months. During these months, it can get hot and humid if you venture away from the sea breeze or don’t have an air-conditioned room. The rainy season runs from June through October (which is also hurricane season). Rainfall doesn’t affect water visibility, as there is very little run-off. Cozumel is blessed with great visibility because of its strong currents. Cold fronts blowing down from the north can make temperatures fall during the coldest winter months, but Cozumel, because of its size and proximity to the mainland, is usually less affected than most Caribbean islands. Water temperatures vary from upper 70s to low 80s.


With no more than three degree’s difference between average summer and winter air temperature and very low annual rainfall, the main factor affecting diving in Curaçao is the wind. The trade winds blow year-round, but are highest from January through April. The best dive months are June through November. Very little diving is done on Curaçao’s north coast because of rough seas. However, for short periods between August and December, the water is calm enough to allow diving. I’ve heard two different tales of diving the north side. One experience involved lots of sharks, the other disappointment. Water temperatures vary from mid-70s in the winter to mid-80s in the summer


Dominica is covered with rain forest and has 365 rivers. As you would expect, it gets a lot of rain, about 70 inches a year along the coast, and up to 400 inches on the interior mountains. I asked a taxi driver on the island how many times a day it rained during the dry season. He replied, “Once or twice.” And during the rainy season? “Sometimes it rains 12 times a day, other times it starts and doesn’t stop for days.” Fortunately the area most dived, around Roseau, gets only about a fourth of what the rest of the island gets. That much rain does affect hiking in the interior. And it’s a great island to hike, as long as you bring a poncho and a sweater. It can get cool, especially at altitude. For a mountainous island, the run-off doesn’t affect the water clarity as much as you would expect. The dry season is from February to mid-June


Fiji’s weather presents a real mixed bag. The choice is often between good visibility and cool water or warm water and calmer seas with less visibility. June through October is the dry season when the water is the clearest, but it’s also at its coldest and the winds kick up. Water temperatures can sink into the low 70s during this time of the year, making it necessary to drag out the full wetsuits. November brings a transition period. The water warms up, the winds die down, and the plankton blooms, lowering the visibility. By January and February, the water has warmed back up into the low 80s. The rains pick up and the hurricane season is on (December through March). Counting Tonga and Samoa, the area gets about five cyclones a year. It’s a risky time to try to catch good diving weather. Because the winds kick up so much in February and March, some resorts pick these months to close down for repairs. During April and May, the wind, and therefore the seas, become calmer and the water remains warm, but the plankton bloom cuts down on the underwater visibility. Of course, this offers the best odds of seeing large plankton eaters. The best time to go depends on your preferences: warm, calmer, cloudy seas, or clear but cold water.


The water temperature is generally about 70° from January to April (the rainy season) and about 66° the rest of the year. Land temperatures also rise during the rainy season, resulting in some uncomfortably hot weather (average daily high is 88°, but it can get much hotter). Visibility tends to drop during the rainy months of February, March, and April. Best months for diving are December and January, then again in May and June. October is probably the worst month, cold and windy. More whale shark sightings are reported during May and June.


Temperatures in Hawaii vary little, remaining in the 80s most of the year. From November through March, occasional cool spells drop temperatures down into the low 70s (rarely into the 60s). Winds become more variable, and storms are more likely. Water temperatures vary from the low 70s to the mid 80s. The weather is warmest and driest from May to October, with persistent winds. There is no set hurricane season as there is in the Caribbean. The tourist off-season is from September to early December and again from mid-April to early June. Humpback season is from November to May.

The Bay Islands (Honduras)
During our coldest winter months, northers can blow down and disrupt the diving. The rainy season starts in October or November and runs into February, but it doesn’t usually affect visibility that much. The no-see-ums are usually the worst during wet weather. The hottest months are March and August.


The thousands of Indonesian islands are spread out over mainly an equatorial tropical climate, but the diving season is as complex as everything else about this diverse amalgam of a country. Avoid the wet monsoon season, generally December through the middle of March. The dry monsoon of southeast winds curtails the diving in Flores during July and August. The Moluccas, however, have their wet monsoons the reverse of everyone else, in July and August, and diving should be avoided then. Depending on your specific destination, April-May and September are the best all-round months to dive


The right time for land packages with game viewing is a complicated affair; animal migrations are scheduled by rain, not calendars. The diving is simpler: September through March is when the winds should be favorable. Whale sharks often cruise the coast about February.


Air temperatures uniformly remain in the 80s year-round. For land travel, there’s little difference between the wet and dry season, although January through March is considered the most comfortable season because of lower humidity and slightly cooler temperatures. Although visibility is slightly reduced by run-off during the July through October monsoons, the wind is also milder during this season, producing flatter seas. Water temperatures remain in the mid 80s year-round. Typhoons are most frequent between August and December but are rare in Palau.

Papua New Guinea

PNG’s weather is dependent on local topography. Heat and humidity are reasonable considerations. Only in the Highlands does it get cool at night. The driest time of year is May through October, but it rains considerably even then. During the rest of the year, plankton blooms are more common. Although Walindi Plantation Resort accommodates guests year-round, January, February, and March are the wettest months. Some boats beat the rainy weather by moving to the other side of the mountains at Kandrian, miraculously transporting to a dry climate. It’s a bit of a steam for the crew, but for guests, it’s a quick flight over the mountains by small plane. The water temperature is a wonderfully warm 84 degrees, and the nights are T-shirt comfortable. The heaviest rains occur in the Rabaul area between January and April.

Rangiroa (French Polynesia)

Rangiroa is diveable year-round, with water temperatures of 79°-83° F. There are really only three seasons of interest to the traveling diver: the manta ray season, from early September through mid-October; the hammerhead shark season, January and February; and the rest of the year, during which an assortment of fish may be seen, with the exception of the two just mentioned (although during May, I did see one manta ray, and a hungry hammerhead stalking it). If you are particular about land weather conditions, you should know that the rainy season is November through December, and the windy season is July and August.

Red Sea

Air temperatures in winter range from 60°-75°; the water can drop down into the upper 60s, with the coolest temperatures occurring in February. Summer land temperatures slide right up past 100°, with the water temperature rising into the low 80s (take a wetsuit anyway). The hottest month is August. If you are going to do any land exploration (and how do you visit the Red Sea without at least a peek at the pyramids), the trade-off for warm water is hot weather. The manta season is from March to June.


On Saba’s mountaintop, it can drop to 65° at night, so travel with a jacket or sweater is recommended. Daytime temperatures range from the upper 70s to mid 80s. The most rain falls during the month of November, but run-off doesn’t affect the diving that much because the best sites are offshore seamounts. Saba is in the hurricane belt (see Caribbean).


The Seychelles Islands are widely spread out in the Indian Ocean, resulting in greatly varying winds, currents, and rainfall. For instance, the main island of Mahé has an annual rainfall of approximately 100 inches, while the western atoll of Aldabra receives only 39 inches a year. Generally speaking, the wettest months are December, January and February. Land temperatures are consistent throughout the year, rarely dropping below 76°. Rain, algae blooms, and winds affect the diving conditions. The Seychelles are mostly unaffected by cyclones. Diving is possible year-round; the best months are considered to be April/May and October/November.

Solomon Islands

The Solomons are hot and humid year-round, with the most rain falling between December and March. Annual rainfalls are well above 100 inches, but mountainous islands do produce rain shadows resulting in much less rainfall on some coasts. Between December and April winds blow periodically out of the west (calm spells are broken by storms). The southeast trades blow from the end of April to November. The better months to travel are probably July through September when the rainfall (and therefore malarial mosquitoes), heat, and humidity are lowest, or in November when there’s a good chance the seas are flat.

St. Vincent

Air temperatures normally stay within 78° to 82° year-round. The rainy season is from May to November, with the mountains of St. Vincent getting more rain than the lower-lying Grenadines.


Tonga’s 170 islands cover a long distance in latitude, but their climates don’t differ all that much. The average air temperature in the northern islands is 80°, while the southern islands average 74°, ranging from a cool 59° in the winter (July to September) to a high in the lower 80s in the summer (December to April). By November, the water temperatures reach the mid 80s, then drop down as low as 70° during their winter months. December through April is also the rainy season, with the most rain falling in February and March. Tonga is prone to tropical cyclones, getting an average of a couple each year. They usually develop in the south and move north, meaning that the odds go up in the northern islands. Cyclones happen as late as May but are most likely during November to March.

Turks & Caicos

During the rainy season, June through November, average monthly rainfall averages about 2.5 inches a month. The dry season runs from January to May, and the monthly average drops to about 1 inch. Winter temperatures can drop to 60° but average about 77°. Bring a jacket for evenings. I’ve been diving here in the winter when the wind was kicking up and it felt chilly. Northers can disrupt the diving periodically. Summer brings temperatures back up into the 90s. Water temperatures range from a low of 71° in winter to a high in the low 80s during summer.

Virgin Islands, British

Mild temperatures vary from mid-70s in winter to lower 90s in summer. Wind is the predominant factor affecting diving. It blows much harder during winter. Also, storms in the North Atlantic bring large swells to the island’s north shores, making divers move to a south lee. Hurricane season is typical Caribbean.

Virgin Islands, U.S.

Winter air temperatures average about 77°, with water temperatures down into the mid 70s. Summer air temperatures average 83°, with water temperatures in the mid 80s. Heavy fall and winter rains affect water visibility. Winter also blows up some heavy winds, making divers search for a lee. Hurricane season is typical Caribbean.

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