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Average Weather in April in Imperial California, United States

In Imperial, the month of April is characterized by rising daily high temperatures, with daily highs increasing by 7°F, from 83°F to 90°F over the course of the month, and rarely exceeding 99°F or dropping below 73°F.

Daily low temperatures increase by 6°F, from 54°F to 60°F, rarely falling below 47°F or exceeding 67°F.

For reference, on July 22, the hottest day of the year, temperatures in Imperial typically range from 80°F to 107°F, while on January 1, the coldest day of the year, they range from 42°F to 68°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 Imperial1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303012 AM4 AM8 AM12 PM4 PM8 PM12 AMMarMayhotcoldcoolwarmcomfortablesweltering
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < very cold < 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 Imperial experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 23% to 18%.

The clearest day of the month is April 29, with clear, mostly clear, or partly cloudy conditions 82% of the time.

For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 35%, while on September 18, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 90%.

Cloud Cover Categories in April

Cloud Cover Categories in April in Imperial181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%MarMayApr 177%Apr 177%Apr 3082%Apr 3082%Apr 1179%Apr 1179%Apr 2179%Apr 2179%clearovercastmostly clearpartly cloudymostly cloudy
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 Imperial, the chance of a wet day over the course of April is gradually decreasing, starting the month at 5% and ending it at 2%.

For reference, the year's highest daily chance of a wet day is 11% on February 17, and its lowest chance is 1% on June 26.

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 Imperial is essentially constant, remaining about 0.2 inches throughout, and rarely exceeding 0.7 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 Imperial, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 55 minutes, implying an average daily increase of 1 minute, 54 seconds, and weekly increase of 13 minutes, 18 seconds.

The shortest day of the month is April 1, with 12 hours, 33 minutes of daylight and the longest day is April 30, with 13 hours, 28 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 Imperial is 6:29 AM on April 1 and the earliest sunrise is 34 minutes earlier at 5:55 AM on April 30.

The earliest sunset is 7:02 PM on April 1 and the latest sunset is 21 minutes later at 7:23 PM on April 30.

Daylight saving time is observed in Imperial during 2017, but it neither starts nor ends during April, so the entire month is in daylight saving time.

For reference, on June 21, the longest day of the year, the Sun rises at 5:34 AM and sets 14 hours, 19 minutes later, at 7:53 PM, while on December 21, the shortest day of the year, it rises at 6:41 AM and sets 9 hours, 59 minutes later, at 4:40 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in April

Sunrise & Sunset with Twilight and Daylight Saving Time in April in Imperial1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303012 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMMarMay5:55 AM5:55 AMApr 307:23 PMApr 307:23 PM6:29 AM6:29 AMApr 17:02 PMApr 17:02 PM6:17 AM6:17 AMApr 117:09 PMApr 117:09 PM6:05 AM6:05 AMApr 217:17 PMApr 217:17 PMSolarMidnightSolarMidnightSolarNoonSunriseSunset
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 Imperial is essentially constant during April, remaining around 0% throughout.

For reference, on August 12, the muggiest day of the year, there are muggy conditions 37% of the time, while on November 21, the least muggy day of the year, there are muggy conditions 0% of the time.

Humidity Comfort Levels in April

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 Imperial is gradually increasing during April, increasing from 8.7 miles per hour to 9.5 miles per hour over the course of the month.

For reference, on May 7, the windiest day of the year, the daily average wind speed is 9.6 miles per hour, while on January 11, 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 Imperial throughout April is predominantly from the west, with a peak proportion of 69% on April 30.

Wind Direction in April

Wind Direction in April in Imperial181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%MarMaywestnortheastsouth
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).

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 Imperial is increasing during April, rising by 1.1 kWh, from 6.8 kWh to 7.9 kWh, over the course of the month.

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 Imperial are 32.848 deg latitude, -115.569 deg longitude, and -56 ft elevation.

The topography within 2 miles of Imperial is essentially flat, with a maximum elevation change of 23 feet and an average elevation above sea level of -56 feet. Within 10 miles is essentially flat (308 feet). Within 50 miles contains only modest variations in elevation (6,565 feet).

The area within 2 miles of Imperial is covered by cropland (71%) and shrubs (29%), within 10 miles by cropland (85%), and within 50 miles by shrubs (50%) and bare soil (20%).

Data Sources

This report illustrates the typical weather in Imperial 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 Imperial.

For each station, the records are corrected for the elevation difference between that station and Imperial 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 Imperial is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Imperial and a given station.

The stations contributing to this reconstruction are: Imperial County Airport (100%, 1.8 kilometers, southwest); Yuma International Airport (0.3%, 92 kilometers, east); and Blythe Airport (0.2%, 117 kilometers, northeast).

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.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.