This report describes the typical weather at the Robert L. Bradshaw International Airport (Basseterre, St. Kitts and Nevis) weather station over the course of an average year. It is based on the historical records from 1999 to 2012. Earlier records are either unavailable or unreliable.
Basseterre has a tropical monsoon climate with short dry season. The area within 25 mi of this station is covered by oceans and seas (95%), grasslands (3%), and forests (2%).
Over the course of a year, the temperature typically varies from 74°F to 88°F and is rarely below 72°F or above 90°F.
The warm season lasts from July 14 to October 17 with an average daily high temperature above 87°F. The hottest day of the year is September 6, with an average high of 88°F and low of 79°F.
The cold season lasts from December 7 to March 20 with an average daily high temperature below 84°F. The coldest day of the year is February 20, with an average low of 74°F and high of 83°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 11:05 hours of daylight; the longest day is June 20 with 13:10 hours of daylight.
The earliest sunrise is at 5:35am on June 4 and the latest sunset is at 6:50pm on July 7. The latest sunrise is at 6:44am on January 21 and the earliest sunset is at 5:34pm on November 20.
Daylight saving time (DST) is not observed in 2012.
The median cloud cover ranges from 49% (partly cloudy) to 68% (partly cloudy). The sky is cloudiest on May 21 and clearest on January 7. The clearer part of the year begins around June 30. The cloudier part of the year begins around April 12.
On January 7, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 40% of the time, and overcast or mostly cloudy 16% of the time.
On May 21, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 50% of the time, and clear or mostly clear 15% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around October 17, occurring in 45% of days. Precipitation is least likely around March 28, occurring in 30% of days.
Over the entire year, the most common forms of precipitation are light rain, moderate rain, and thunderstorms.
Light rain is the most severe precipitation observed during 58% of those days with precipitation. It is most likely around January 3, when it is observed during 27% of all days.
Moderate rain is the most severe precipitation observed during 23% of those days with precipitation. It is most likely around April 27, when it is observed during 10% of all days.
Thunderstorms are the most severe precipitation observed during 19% of those days with precipitation. They are most likely around September 15, when it is observed during 18% of all days.
During the warm season, which lasts from July 14 to October 17, there is a 41% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of light rain (43% of days with precipitation have at worst light rain), thunderstorms (36%), and moderate rain (19%).
During the cold season, which lasts from December 7 to March 20, there is a 34% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of light rain (71% of days with precipitation have at worst light rain) and moderate rain (26%).
Either snow is exceptionally unlikely to fall at any time during the year at this location or this station does not reliably report precipitation types.
The relative humidity typically ranges from 63% (mildly humid) to 91% (very humid) over the course of the year, rarely dropping below 54% (mildly humid) and reaching as high as 99% (very humid).
The air is driest around February 29, at which time the relative humidity drops below 67% (mildly humid) three days out of four; it is most humid around October 17, exceeding 88% (very humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a year, the dew point typically varies from 66°F (muggy) to 78°F (oppressive) and is rarely below 62°F (mildy humid) or above 79°F (oppressive).
Over the course of the year typical wind speeds vary from 3 mph to 16 mph (light breeze to moderate breeze), rarely exceeding 21 mph (fresh breeze).
The highest average wind speed of 12 mph (moderate breeze) occurs around June 29, at which time the average daily maximum wind speed is 15 mph (moderate breeze).
The lowest average wind speed of 8 mph (gentle breeze) occurs around September 22, at which time the average daily maximum wind speed is 12 mph (moderate breeze).