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Anguilla is low and dry, with an annual rainfall of about 40 inches.
Dry season starts in January and runs through April. The rainy season is from
August to November. However, there is very little run-off, so diving is generally
not affected by the rain. The odds of hurricanes are small; the average is only
one every 20 years (see Caribbean below).
Dry season is typical for the Caribbean - from January to April,
with the rainy season from August to November. Antigua is a relatively dry island,
with an annual rainfall of 44 inches. Odds of a hurricane are small; on average,
Antigua experiences only one hurricane every 20 years (see Caribbean below).
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. Summer weather is sultry and oppressive, with tropical showers.... Water temperature is below 80 and colder in their winter, so bring rubber; visibility can at times be in the 50-foot range. That's the easy part. From there, it gets increasingly complex; Australia's diving areas are vast. 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 vis at Osprey, in the northern Coral Sea, is between June and September. 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 islands south of Nassau (such as Great Exuma, San Salvador, and Long Island) usually manage to stay a degree or two warmer. Easterly trade winds predominate for most of the year, but there is usually a lee to be found for diving.
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 30' 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.
Bermuda is surprisingly far north, located on about the same latitude
as Dallas, TX. Winds blow out of the south for most of the summer. In the winter,
storms from the west and northwest are common. Water temperature varies from low
60s during the winter to summer highs in the 80s. The average yearly rainfall
of 57 inches is generally evenly distributed throughout the year.
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
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
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 30' 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.
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 100' to 50'
the next day, and heavy flotsam and debris floated in on the surface. But even
then, some dives would have great visibility below 40', while other sites still
had 100' vis right below the surface.
During our July visit, the seas were flat except for one day
when the wind kicked up. The ocean is roughest between November and February.
The best season is between April and September, but diving is year-round.
Burma is hot and humid throughout the year. The dry and cool season runs from November to February. March to May is also dry but very hot. The rainy season runs from May to October. Monsoons during this period have kept liveaboards from visiting the popular Burma Banks, or even from leaving port, so liveaboards generally operate only between November and early May.
Most British Columbia diving takes place from late Spring to early Fall. The Nautilus Explorer, for instance, heads to Mexico after August. In Nova Scotia, the Gulf Stream warms the ocean surface to 64° F in summer.
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
October, all over.
The 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
Easter Island’s subtropical water temperatures average 70°F, with the warmest waters (72°F) from September into February. Air temperatures range from highs of 68°F in summer months to 79°F in winter. Conditions make for easy diving in the winter, but rough waters can limit choices of dive sites in summer.
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
Our suggestions for the dive season on the Pacific coast (the only decent diving in Costa Rica) may seem odd. The
best time to go is the rainy season (May through November), even though runoff can affect the water visibility.
The water clarity may be better during the dry season, but the wind blows up enough to make it almost impossible
to get out to the best dive sites, which are small islands or rock outcroppings an hour's boat ride from the mainland.
Visibility is a crap-shoot any time of the year, but even more so during the rainy season. However, even during
the wet months there is a slight chance that offshore sites can reach almost 100 foot vis, although less than forty
is more common. The best scheduling would probably be May, when the wind has died down and the rain hasn't started
yet. Water temperatures run between 75° and 85° year-round.
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. Also, sharks go deep in El Niño years, so these years are not
a good time to see big creatures.
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.
Grenada stays at about 80° year-round. Dry season is January
to May. During the rainy season (June through December), there are usually brief
showers daily. Hurricanes are infrequent.
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.
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 season for diving Indonesia is as complex as
everything else about this diverse amalgam of a country. Your diving Indonesia experience will probably be enhanced if you plan around the wet monsoon
season, generally December through the middle of March, in many areas; though Raja Ampat diving is generally better and more popular then due to calmer seas. 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 Indonesia (with the exception of Raja Ampat as noted).
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.
Rainy season runs from mid-May to late November and the dry season is from December to May. However, September and October usually have the driest weather and flattest seas, even though it is the wet season. Average temperature is around 90ºF during the day and 72ºF at night. Winter winds create choppy seas which may prevent the dive pangas from getting to some sites. Visibility can range from 20 to 80 feet, depending on conditions. Water temperatures are in the low to mid-80s year round.
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 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.
Air temperatures in winter range from 60°-75°; thewater 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
Winter air temperatures range between 65° and 85°; summer's
between 75° and 95°. The dry season is from February to May, and the wet
season runs from June to November.
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 & the Grenadines
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.
Temperatures remain mostly in the 80s year-round. The rainy season
is from May to December, interrupted by a short dry season in late September and
October. A longer dry season occurs from January to May. The island is mainly
out of the hurricane belt
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
May to October is the dryer, cooler season, but trade winds can
be erratic and strong. Depending on your location in north or south Vanuatu, winter
air temperatures average from 63° to 68°. The summer months of November
to April are rainy with extremely high humidity and air temps in the mid-80s but
generally light winds. Water temperatures run from 83° in February down to
as low as 68° in September (the northern islands have slightly warmer temperatures
than the southern islands). Cyclones average about one per year, occurring generally
between December and March, with the peak month being January.
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