Average Weather in Saint Croix U.S. Virgin Islands
In Saint Croix, the temperature typically varies from 72°F to 88°F over the course of the year, and is rarely below 68°F or above 90°F.
The hot season lasts for 4.0 months, from June 15 to October 16, with an average daily high temperature above 87°F. The hottest day of the year is August 19, with an average high of 88°F and low of 78°F.
The cool season lasts for 3.4 months, from December 14 to March 26, with an average daily high temperature below 84°F. The coldest day of the year is January 22, with an average low of 72°F and high of 83°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature
The length of the day in Saint Croix varies over the course of the year. In 2017, the shortest day is December 21, with 11 hours, 4 minutes of daylight; the longest day is June 21, with 13 hours, 12 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:43 AM on June 5, and the latest sunrise is 1 hour, 10 minutes later at 6:53 AM on January 19. The earliest sunset is at 5:41 PM on November 23, and the latest sunset is 1 hour, 16 minutes later at 6:58 PM on July 6.
Daylight saving time (DST) is not observed in Saint Croix during 2017.
Sunrise & Sunset with Twilight
In Saint Croix, the average percentage of the sky covered by clouds experiences extreme seasonal variation over the course of the year.
The clearer part of the year in Saint Croix begins around November 18 and lasts for 5.4 months, ending around April 29. On January 11, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 81% of the time, and overcast or mostly cloudy 19% of the time.
The cloudier part of the year begins around April 29 and lasts for 6.6 months, ending around November 18. On May 30, the cloudiest day of the year, the sky is overcast or mostly cloudy 72% of the time, and clear, mostly clear, or partly cloudy 28% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Saint Croix varies throughout the year.
The wetter season lasts 7.2 months, from April 26 to December 2, with a greater than 17% chance of a given day being a wet day. The chance of a wet day peaks at 28% on November 1.
The drier season lasts 4.8 months, from December 2 to April 26. The smallest chance of a wet day is 6% on January 24.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 28% on November 1.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day in the year. Saint Croix experiences significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 9.7 months, from March 25 to January 15, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around November 4, with an average total accumulation of 2.6 inches.
The rainless period of the year lasts for 2.3 months, from January 15 to March 25. The least rain falls around January 31, with and average total accumulation of 0.4 inches.
Average Monthly Rainfall
We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.
Saint Croix experiences some seasonal variation in the perceived humidity.
The muggier period of the year lasts for 9.9 months, from April 3 to February 1, during which time the comfort level is muggy, oppressive, or miserable at least 79% of the time. The muggiest day of the year is September 20, with muggy conditions 99% of the time.
The least muggy day of the year is March 8, with muggy conditions 72% of the time.
Humidity Comfort Levels
This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.
The average hourly wind speed in Saint Croix experiences mildly seasonal variation over the course of the year.
The windier part of the year lasts for 2.7 months, from June 2 to August 25, with average wind speeds of more than 7.6 miles per hour. The windiest day of the year is July 13, with an average hourly wind speed of 8.8 miles per hour.
The calmer time of year lasts for 9.2 months, from August 25 to June 2. The calmest day of the year is October 10, with an average hourly wind speed of 6.5 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Saint Croix is from the east throughout the year.
Saint Croix is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average water temperature experiences some seasonal variation over the course of the year.
The time of year with warmer water lasts for 3.4 months, from August 2 to November 13, with an average temperature above 83°F. The day of the year with the warmest water is September 18, with an average temperature of 84°F.
The time of year with cooler water lasts for 3.1 months, from January 9 to April 12, with an average temperature below 80°F. The day of the year with the coolest water is February 26, with an average temperature of 79°F.
Average Water Temperature
This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.
The average daily incident shortwave solar energy experiences some seasonal variation over the course of the year.
The brighter period of the year lasts for 1.9 months, from March 7 to May 4, with an average daily incident shortwave energy per square meter above 6.6 kWh. The brightest day of the year is April 3, with an average of 7.2 kWh.
The darker period of the year lasts for 3.7 months, from September 13 to January 5, with an average daily incident shortwave energy per square meter below 5.1 kWh. The darkest day of the year is October 24, with an average of 4.6 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Saint Croix are 17.728 deg latitude, -64.747 deg longitude, and 108 ft elevation (map ).
The topography within 2 miles of Saint Croix contains significant variations in elevation, with a maximum elevation change of 584 feet, and an average elevation above sea level of 195 feet. Within 10 miles contains very significant variations in elevation (1,158 feet). Within 50 miles also contains very significant variations in elevation (1,781 feet).
The area within 2 miles of Saint Croix is covered by grassland (44%), trees (26%), water (14%), and shrubs (10%), within 10 miles by water (77%), and within 50 miles by water (98%).
This report illustrates the typical weather in Saint Croix, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Saint Croix.
For each station, the records are corrected for the elevation difference between that station and Saint Croix according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Saint Croix is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Saint Croix and a given station.
The stations contributing to this reconstruction are: Henry E Rohlsen Airport (96%, 8 kilometers, southwest), Cyril E. King Airport (3.4%, 72 kilometers, north), and Princess Juliana International Airport (0.9%, 176 kilometers, east).
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.
Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.
Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .
Time zones for aiports and weather stations are provided by AskGeo.com .