Antigua and
Barbuda has a tropical maritime wet and dry type climate. The main
drivers of the climate are tropical sea surface temperatures of the
Pacific and Atlantic Oceans. The islands experience neither frost,
snow, sleet, hail nor extremes of temperatures. A unique exception
to that, however, occurred on April 16, 1993, when parts of Antigua
experienced showers of hail over a 3 hour interval around sunrise.
Rainfall
There are two
main seasons: the dry season - January to June and the wet season -
July to December; these seasons account for 36 and 64% respectively
of the annual total rainfall. The normal annual rainfall total is
1187.5 mm (46.75 in) but ranges from 681.48 mm to 1764.0 mm (26.83
to 69.45 in). The driest and wettest months are March, with 51.8 mm
(2.04 in), and October, with 161.0 mm (6.34 in),
respectively.
Temperature
The air
temperature seldom falls below 20°C
(68°F) and seldom ever rises
above 32°C (89.6°F). On record, the extremes are 16.1°C (61.0°F)
and 34.9°C (94.8°F). Meanwhile, the mean daily temperature is
26.9°C (80.4°F). The warmest and coolest months are February
with 25.2°C (77.4°F) and August with 28.3°C (82.9°F) respectively.
The
mean sea surface temperature is around 27.6°C (81.7°F) with mean
rising to around 28.9°C (84.0°F) in September and falling to around 26.2°C
(79.2°F) in February and March.
Hours of Sunshine
The hours of
bright sunshine ranges from 8 to 9.5 hours on average. There is
seldom ever a day without bright sunshine. The length of day (the
interval between sunrise and sunset) varies from 11 hours and 6
minutes in December to 13 hours and 9 minutes in late June.
Humidity
Humidity is
fairly high and uniform from month to month. The mean relative
humidity is 76% ranging from 73% in March and 79% in October. The
relatively high humidity values are fairly deceptive as the trade
winds continuously bring refreshing breezes across the islands.
Thus, the high humidity is often not a issue for most persons.
Winds
The trade
winds basically blow continuously across the area from the east at a
mean speed of 11.5 knots (13.2 mph). The windiest month is July with
13.6 knots (15.6 mph) and the calmest is October with 9.2 knots
(10.6 mph). The winds seldom exceeds 21 knots (24 mph) and hardly
ever calm.
Hurricanes
Hurricanes may
occur any time from June through November; however, historically,
the most likely time is mid August to mid September. There is a 25%
chance of a hurricane affecting Antigua in a given year or once
every four years.
Droughts
Droughts are a
regular occurrence of the climate of Antigua and Barbuda. Rainfall
is highly variable especially from month to month. From time to
time, these droughts can be quite severe and last for more than a
year.
Climate Change
Under climate change, Antigua is projected to get drier and warmer.
However, the record for both rainfall and temperature show an upward
trend.