This report describes the typical weather at the Cyril E. King Airport (St. Thomas, US Virgin Islands) weather station over the course of an average April. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
St. Thomas has a tropical savanna climate with dry winters. The area within 25 mi of this station is covered by oceans and seas (99%).
The month of April is characterized by essentially constant daily high temperatures, with daily highs around 85°F throughout the month, exceeding 90°F or dropping below 82°F only one day in ten.
Over the course of April, the length of the day is essentially constant. The shortest day of the month is April 1 with 12:20 hours of daylight; the longest day is April 30 with 12:48 hours of daylight.
The earliest sunrise is at 5:53am on April 30; the latest sunset is at 6:41pm on April 29; the latest sunrise is at 6:14am on April 1; the earliest sunset is at 6:33pm on April 1.
Daylight savings time (DST) is not observed in 2012.
The median cloud cover is 22% (mostly clear) and does not vary substantially over the course of the month.
On April 15, a representative day, the sky is clear or mostly clear 51% of the time, partly cloudy 6% of the time, and mostly cloudy or overcast 18% of the time.
The average probability that some form of precipitation will be observed in a given day is 23%, with little variation over the course of the month.
Throughout April, the most common forms of precipitation are light rain, moderate rain, and heavy rain.
Light rain is the most severe precipitation observed during 51% of those days with precipitation. It is most likely around April 6, when it is observed during 12% of all days.
Moderate rain is the most severe precipitation observed during 25% of those days with precipitation. It is most likely around April 1, when it is observed during 6% of all days.
Heavy rain is the most severe precipitation observed during 22% of those days with precipitation. It is most likely around April 17, when it is observed during 5% of all days.
Either snow is exceptionally unlikely to fall at this location in April or this station does not reliably report precipitation types.
The relative humidity typically ranges from 57% (mildly humid) to 84% (humid) over the course of a typical April, rarely dropping below 46% (comfortable), or exceeding 94% (very humid).
The air is driest around April 1, at which time the relative humidity drops below 64% (mildly humid) three days out of four; it is most humid around April 29, rising above 79% (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 typical April, the dew point typically varies from 66°F (muggy) to 73°F (very muggy) and is rarely below 60°F (comfortable) or above 77°F (oppressive).
Over the course of April typical wind speeds vary from 6 mph to 17 mph (light breeze to moderate breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 11 mph (gentle breeze) occurs around April 7, at which time the average daily maximum wind speed is 17 mph (moderate breeze).
The lowest average wind speed of 10 mph (gentle breeze) occurs around April 28, at which time the average daily maximum wind speed is 16 mph (moderate breeze).