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  5. April

Average Weather in April in Saint Croix U.S. Virgin Islands

In Saint Croix, the month of April is characterized by essentially constant daily high temperatures, with daily highs around 84°F throughout the month, rarely exceeding 87°F or dropping below 82°F.

Daily low temperatures increase by 2°F, from 73°F to 75°F, rarely falling below 70°F or exceeding 78°F.

For reference, on August 19, the hottest day of the year, temperatures in Saint Croix typically range from 78°F to 88°F, while on January 22, the coldest day of the year, they range from 72°F to 83°F.

Average High and Low Temperature in April

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on April. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature in April

Average Hourly Temperature in April in Saint Croix12 AM4 AM8 AM12 PM4 PM8 PM12 AM18152229112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030MarMaycomfortablewarmhot
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < chilly < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Clouds

The month of April in Saint Croix experiences very rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 27% to 47%.

The clearest day of the month is April 1, with clear, mostly clear, or partly cloudy conditions 73% of the time.

For reference, on May 30, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 72%, while on January 11, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 81%.

Cloud Cover in April

The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Saint Croix, the chance of a wet day over the course of April is very rapidly increasing, starting the month at 9% and ending it at 19%.

For reference, the year's highest daily chance of a wet day is 28% on November 1, and its lowest chance is 6% on January 30.

Probability of Precipitation in April

The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during April in Saint Croix is increasing, starting the month at 0.6 inches, when it rarely exceeds 1.4 inches, and ending the month at 1.5 inches, when it rarely exceeds 3.6 inches or falls below 0.1 inches.

Average Monthly Rainfall in April

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Sun

Over the course of April in Saint Croix, the length of the day is gradually increasing. From the start to the end of the month, the length of the day increases by 27 minutes, implying an average daily increase of 56 seconds, and weekly increase of 6 minutes, 35 seconds.

The shortest day of the month is April 1, with 12 hours, 19 minutes of daylight and the longest day is April 30, with 12 hours, 46 minutes of daylight.

Hours of Daylight and Twilight in April

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The latest sunrise of the month in Saint Croix is 6:13 AM on April 1 and the earliest sunrise is 20 minutes earlier at 5:53 AM on April 30.

The earliest sunset is 6:32 PM on April 1 and the latest sunset is 7 minutes later at 6:39 PM on April 30.

Daylight saving time is not observed in Saint Croix during 2017.

For reference, on June 21, the longest day of the year, the Sun rises at 5:45 AM and sets 13 hours, 12 minutes later, at 6:56 PM, while on December 21, the shortest day of the year, it rises at 6:45 AM and sets 11 hours, 4 minutes later, at 5:49 PM.

Sunrise & Sunset with Twilight in April

The solar day over the course of April. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

Humidity

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.

The chance that a given day will be muggy in Saint Croix is rapidly increasing during April, rising from 78% to 92% over the course of the month.

For reference, on September 18, the muggiest day of the year, there are muggy conditions 99% of the time, while on March 6, the least muggy day of the year, there are muggy conditions 72% of the time.

Humidity Comfort Levels in April

Humidity Comfort Levels in April in Saint Croix0%10%20%30%40%50%60%70%80%90%100%18152229112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030MarMayApr 178%Apr 178%Apr 3092%Apr 3092%Apr 1182%Apr 1182%Apr 2188%Apr 2188%miserablemiserableoppressiveoppressivemuggymuggyhumidhumidcomfortablecomfortable
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

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 is essentially constant during April, remaining within 0.1 miles per hour of 7.3 miles per hour throughout.

For reference, on July 13, the windiest day of the year, the daily average wind speed is 8.8 miles per hour, while on October 10, the calmest day of the year, the daily average wind speed is 6.5 miles per hour.

Average Wind Speed in April

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
The hourly average wind direction in Saint Croix throughout April is predominantly from the east, with a peak proportion of 88% on April 2.

Wind Direction in April

The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

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 surface water temperature in Saint Croix is essentially constant during April, remaining within 1°F of 80°F throughout.

Average Water Temperature in April

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

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 in Saint Croix is essentially constant during April, remaining within 0.2 kWh of 7.0 kWh throughout.

The highest average daily incident shortwave solar energy during April is 7.2 kWh on April 3.

Average Daily Incident Shortwave Solar Energy in April

The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

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.

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 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%).

Data Sources

This report illustrates the typical weather in Saint Croix year round, 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).

Other Data

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 .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.