Average Weather in April in San Jose California, United States
In San Jose, the month of April is characterized by gradually rising daily high temperatures, with daily highs increasing by 4°F, from 68°F to 73°F over the course of the month, and rarely exceeding 84°F or dropping below 59°F.
Daily low temperatures increase by 3°F, from 48°F to 52°F, rarely falling below 43°F or exceeding 57°F.
For reference, on August 24, the hottest day of the year, temperatures in San Jose typically range from 59°F to 82°F, while on December 31, the coldest day of the year, they range from 42°F to 59°F.
Average High and Low Temperature in April
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
The month of April in San Jose experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 47% to 39%.
The clearest day of the month is April 28, with clear, mostly clear, or partly cloudy conditions 61% of the time.
For reference, on January 11, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 56%, while on July 29, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 92%.
Cloud Cover in April
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In San Jose, the chance of a wet day over the course of April is very rapidly decreasing, starting the month at 18% and ending it at 10%.
For reference, the year's highest daily chance of a wet day is 30% on February 21, and its lowest chance is -0% on July 22.
Probability of Precipitation in April
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 San Jose is rapidly decreasing, starting the month at 1.9 inches, when it rarely exceeds 4.7 inches or falls below 0.2 inches, and ending the month at 0.8 inches, when it rarely exceeds 2.1 inches.
Average Monthly Rainfall in April
Over the course of April in San Jose, 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, 5 minutes, implying an average daily increase of 2 minutes, 15 seconds, and weekly increase of 15 minutes, 45 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, 43 minutes of daylight.
Hours of Daylight and Twilight in April
The latest sunrise of the month in San Jose is 6:52 AM on April 1 and the earliest sunrise is 39 minutes earlier at 6:13 AM on April 30.
The earliest sunset is 7:30 PM on April 1 and the latest sunset is 26 minutes later at 7:56 PM on April 30.
Daylight saving time is observed in San Jose 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 5:47 AM and sets 14 hours, 44 minutes later, at 8:31 PM, while on December 21, the shortest day of the year, it rises at 7:18 AM and sets 9 hours, 35 minutes later, at 4:53 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in April
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 San Jose is essentially constant during April, remaining around 0% throughout.
For reference, on July 21, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the leasy muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in April
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 San Jose is essentially constant during April, remaining within 0.1 miles per hour of 3.9 miles per hour throughout.
For reference, on June 6, the windiest day of the year, the daily average wind speed is 4.4 miles per hour, while on October 21, the calmest day of the year, the daily average wind speed is 3.2 miles per hour.
Average Wind Speed in April
Wind Direction in April
San Jose 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 San Jose is essentially constant during April, remaining around 53°F throughout.
Average Water Temperature in April
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 San Jose 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
For the purposes of this report, the geographical coordinates of San Jose are 37.339 deg latitude, -121.895 deg longitude, and 95 ft elevation.
The topography within 2 miles of San Jose is essentially flat, with a maximum elevation change of 82 feet and an average elevation above sea level of 86 feet. Within 10 miles is essentially flat (2,861 feet). Within 50 miles contains large variations in elevation (4,318 feet).
The area within 2 miles of San Jose is covered by artificial surfaces (100%), within 10 miles by artificial surfaces (69%) and grassland (18%), and within 50 miles by water (28%) and grassland (22%).
This report illustrates the typical weather in San Jose 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 2 weather stations near enough to contribute to our estimation of the temperature and dew point in San Jose.
For each station, the records are corrected for the elevation difference between that station and San Jose 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 San Jose is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between San Jose and a given station.
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.