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Average Weather in April in Pacheco California, United States

Daily high temperatures increase by 6°F, from 68°F to 73°F, rarely falling below 58°F or exceeding 86°F.

Daily low temperatures increase by 3°F, from 47°F to 51°F, rarely falling below 42°F or exceeding 56°F.

For reference, on July 28, the hottest day of the year, temperatures in Pacheco typically range from 58°F to 87°F, while on December 31, the coldest day of the year, they range from 40°F to 55°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 Pacheco1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303012 AM4 AM8 AM12 PM4 PM8 PM12 AMMarMaycoldcoldcoolcomfortablewarm
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 average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Rengo, Chile (5,989 miles away); Minas, Uruguay (6,589 miles); and Torres Novas, Portugal (5,635 miles) are the far-away foreign places with temperatures most similar to Pacheco (view comparison).

Clouds

The month of April in Pacheco experiences decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 47% to 38%.

The clearest day of the month is April 28, with clear, mostly clear, or partly cloudy conditions 62% of the time.

For reference, on January 11, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 58%, while on July 20, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 92%.

Cloud Cover Categories in April

Cloud Cover Categories in April in Pacheco181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%MarMayApr 153%Apr 153%Apr 3062%Apr 3062%Apr 1157%Apr 1157%Apr 2158%Apr 2158%clearmostly clearmostly cloudyovercastpartly cloudy
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Pacheco, the chance of a wet day over the course of April is rapidly decreasing, starting the month at 17% and ending it at 9%.

For reference, the year's highest daily chance of a wet day is 30% on February 20, and its lowest chance is 0% on August 2.

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 Pacheco is decreasing, starting the month at 1.7 inches, when it rarely exceeds 4.0 inches or falls below 0.1 inches, and ending the month at 0.7 inches, when it rarely exceeds 1.8 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 Pacheco, the length of the day is rapidly increasing. From the start to the end of the month, the length of the day increases by 1 hour, 7 minutes, implying an average daily increase of 2 minutes, 18 seconds, and weekly increase of 16 minutes, 9 seconds.

The shortest day of the month is April 1, with 12 hours, 38 minutes of daylight and the longest day is April 30, with 13 hours, 45 minutes of daylight.

Hours of Daylight and Twilight in April

Hours of Daylight and Twilight in April in Pacheco181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrMarMaynightnightdaydayApr 112 hr, 38 minApr 112 hr, 38 minApr 3013 hr, 45 minApr 3013 hr, 45 min
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 Pacheco is 6:53 AM on April 1 and the earliest sunrise is 40 minutes earlier at 6:13 AM on April 30.

The earliest sunset is 7:31 PM on April 1 and the latest sunset is 27 minutes later at 7:58 PM on April 30.

Daylight saving time is observed in Pacheco during 2018, 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 5:46 AM and sets 14 hours, 48 minutes later, at 8:34 PM, while on December 21, the shortest day of the year, it rises at 7:20 AM and sets 9 hours, 32 minutes later, at 4:52 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in April

Sunrise & Sunset with Twilight and Daylight Saving Time in April in Pacheco181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930302 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMMarMay6:13 AM6:13 AMApr 307:58 PMApr 307:58 PM6:53 AM6:53 AMApr 17:31 PMApr 17:31 PM6:31 AM6:31 AMApr 167:45 PMApr 167:45 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 Pacheco is essentially constant during April, remaining around 0% throughout.

For reference, on May 15, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.

Humidity Comfort Levels in April

dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

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 Pacheco is gradually increasing during April, increasing from 8.1 miles per hour to 8.8 miles per hour over the course of the month.

For reference, on June 22, the windiest day of the year, the daily average wind speed is 10.0 miles per hour, while on November 1, the calmest day of the year, the daily average wind speed is 6.7 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 Pacheco throughout April is predominantly from the west, with a peak proportion of 76% on April 30.

Wind Direction in April

Wind Direction in April in Pacheco181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%20%80%40%60%60%40%80%20%100%0%MarMaywestnorthsouth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 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

Pacheco 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 Pacheco is essentially constant during April, remaining around 53°F throughout.

Average Water Temperature in April

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

Growing Season

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Pacheco typically lasts for 11 months (347 days), from around January 10 to around December 23, rarely starting after February 16, or ending before November 26.

The month of April in Pacheco is reliably fully within the growing season.

Time Spent in Various Temperature Bands and the Growing Season in April

Time Spent in Various Temperature Bands and the Growing Season in April in Pachecogrowing seasongrowing season181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930300%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%MarMay100%Apr 16100%Apr 16very coldcoldcoolcomfortablewarm
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 percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

The average accumulated growing degree days in Pacheco are increasing during April, increasing by 258°F, from 358°F to 616°F, over the course of the month.

Growing Degree Days in April

The average growing degree days accumulated over the course of April, 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 Pacheco is increasing during April, rising by 1.3 kWh, from 5.6 kWh to 6.9 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 Pacheco are 37.984 deg latitude, -122.075 deg longitude, and 66 ft elevation.

The topography within 2 miles of Pacheco contains only modest variations in elevation, with a maximum elevation change of 446 feet and an average elevation above sea level of 105 feet. Within 10 miles contains only modest variations in elevation (2,720 feet). Within 50 miles contains large variations in elevation (4,078 feet).

The area within 2 miles of Pacheco is covered by artificial surfaces (83%) and cropland (14%), within 10 miles by grassland (32%) and artificial surfaces (30%), and within 50 miles by cropland (23%) and grassland (23%).

Data Sources

This report illustrates the typical weather in Pacheco 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 Pacheco.

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

The stations contributing to this reconstruction are: Buchanan Field Airport (97%, 2.0 kilometers, northeast); Napa County Airport (1.6%, 31 kilometers, northwest); and Oakland International Airport (1.5%, 32 kilometers, southwest).

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.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.