This report describes the typical weather at the Henry E. Rohlsen Airport (St. Croix, US Virgin Islands) weather station over the course of an average January. It is based on the historical records from 1991 to 2012. Earlier records are either unavailable or unreliable.
St. Croix has a tropical savanna climate with dry winters. The area within 25 mi of this station is covered by oceans and seas (96%) and forests (2%).
The month of January is characterized by essentially constant daily high temperatures, with daily highs around 83°F throughout the month, exceeding 86°F or dropping below 80°F only one day in ten.
Over the course of January, the length of the day is essentially constant. The shortest day of the month is January 1 with 11:05 hours of daylight; the longest day is January 29 with 11:21 hours of daylight.
The earliest sunrise is at 6:50am on January 1; the latest sunset is at 6:13pm on January 31; the latest sunrise is at 6:54am on January 19; the earliest sunset is at 5:55pm on January 1.
Daylight saving time (DST) is not observed in 2012.
The median cloud cover is 41% (partly cloudy) and does not vary substantially over the course of the month.
On January 16, a representative day, the sky is clear or mostly clear 39% of the time, partly cloudy 24% of the time, and mostly cloudy or overcast 21% of the time.
The average probability that some form of precipitation will be observed in a given day is 40%, with little variation over the course of the month.
Throughout January, the most common forms of precipitation are light rain, moderate rain, and heavy rain.
Light rain is the most severe precipitation observed during 58% of those days with precipitation. It is most likely around January 2, when it is observed during 24% of all days.
Moderate rain is the most severe precipitation observed during 28% of those days with precipitation. It is most likely around January 2, when it is observed during 12% of all days.
Heavy rain is the most severe precipitation observed during 13% of those days with precipitation. It is most likely around January 10, when it is observed during 6% of all days.
Either snow is exceptionally unlikely to fall at this location in January or this station does not reliably report precipitation types.
The relative humidity typically ranges from 61% (mildly humid) to 89% (very humid) over the course of a typical January, rarely dropping below 53% (mildly humid) and reaching as high as 97% (very humid).
The air is driest around January 31, at which time the relative humidity drops below 65% (mildly humid) three days out of four; it is most humid around January 15, rising above 84% (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 January, the dew point typically varies from 66°F (muggy) to 72°F (very muggy) and is rarely below 62°F (mildy humid) or above 75°F (very muggy).
Over the course of January 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 January 7, at which time the average daily maximum wind speed is 17 mph (moderate breeze).
The lowest average wind speed of 11 mph (gentle breeze) occurs around January 15, at which time the average daily maximum wind speed is 17 mph (moderate breeze).