Average Weather at Modesto City-County Airport California, United States
At Modesto City-County Airport, the summers are hot, arid, and clear and the winters are short, cold, wet, and partly cloudy. Over the course of the year, the temperature typically varies from 39°F to 95°F and is rarely below 30°F or above 103°F.
The hot season lasts for 3.6 months, from June 4 to September 23, with an average daily high temperature above 87°F. The hottest day of the year is July 18, with an average high of 95°F and low of 64°F.
The cool season lasts for 2.8 months, from November 22 to February 15, with an average daily high temperature below 62°F. The coldest day of the year is December 31, with an average low of 39°F and high of 54°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
At Modesto City-County Airport, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year at Modesto City-County Airport begins around May 12 and lasts for 5.5 months, ending around October 27. On July 29, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 92% of the time, and overcast or mostly cloudy 8% of the time.
The cloudier part of the year begins around October 27 and lasts for 6.5 months, ending around May 12. On February 6, the cloudiest day of the year, the sky is overcast or mostly cloudy 53% of the time, and clear, mostly clear, or partly cloudy 47% of the time.
Cloud Cover Categories
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at Modesto City-County Airport varies throughout the year.
The wetter season lasts 5.2 months, from November 5 to April 10, with a greater than 14% chance of a given day being a wet day. The chance of a wet day peaks at 28% on February 20.
The drier season lasts 6.8 months, from April 10 to November 5. The smallest chance of a wet day is 0% on July 29.
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 February 20.
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 of the year. Modesto City-County Airport experiences significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 7.3 months, from October 5 to May 14, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around February 15, with an average total accumulation of 3.2 inches.
The rainless period of the year lasts for 4.7 months, from May 14 to October 5. The least rain falls around August 3, with an average total accumulation of 0.0 inches.
Average Monthly Rainfall
The length of the day at Modesto City-County Airport varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 34 minutes of daylight; the longest day is June 20, with 14 hours, 46 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:41 AM on June 13, and the latest sunrise is 1 hour, 51 minutes later at 7:32 AM on November 4. The earliest sunset is at 4:45 PM on December 6, and the latest sunset is 3 hours, 44 minutes later at 8:29 PM on June 27.
Daylight saving time (DST) is observed at Modesto City-County Airport during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.
Sunrise & Sunset with Twilight and Daylight Saving Time
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 perceived humidity level at Modesto City-County Airport, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.
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 at Modesto City-County Airport experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 4.6 months, from April 10 to August 29, with average wind speeds of more than 3.8 miles per hour. The windiest day of the year is June 19, with an average hourly wind speed of 4.6 miles per hour.
The calmer time of year lasts for 7.4 months, from August 29 to April 10. The calmest day of the year is November 2, with an average hourly wind speed of 3.0 miles per hour.
Average Wind Speed
The predominant average hourly wind direction at Modesto City-County Airport varies throughout the year.
The wind is most often from the south for 1.4 weeks, from January 7 to January 17 and for 2.1 weeks, from January 25 to February 9, with a peak percentage of 31% on February 4. The wind is most often from the north for 1.1 weeks, from January 17 to January 25 and for 1.5 months, from November 23 to January 7, with a peak percentage of 29% on January 20. The wind is most often from the west for 9.5 months, from February 9 to November 23, with a peak percentage of 97% on July 18.
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 extreme seasonal variation over the course of the year.
The brighter period of the year lasts for 3.6 months, from May 6 to August 24, with an average daily incident shortwave energy per square meter above 7.2 kWh. The brightest day of the year is June 27, with an average of 8.5 kWh.
The darker period of the year lasts for 3.6 months, from November 3 to February 19, with an average daily incident shortwave energy per square meter below 3.5 kWh. The darkest day of the year is December 23, with an average of 2.2 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Modesto City-County Airport are 37.625 deg latitude, -120.955 deg longitude, and 95 ft elevation.
The topography within 2 miles of Modesto City-County Airport is essentially flat, with a maximum elevation change of 66 feet and an average elevation above sea level of 92 feet. Within 10 miles is essentially flat (174 feet). Within 50 miles contains only modest variations in elevation (4,931 feet).
The area within 2 miles of Modesto City-County Airport is covered by artificial surfaces (82%) and cropland (10%), within 10 miles by cropland (78%) and artificial surfaces (21%), and within 50 miles by cropland (38%) and grassland (37%).
This report illustrates the typical weather at Modesto City-County Airport, 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
Modesto City-County Airport has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.
In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.
The stations on which we may fall back include but are not limited to Stockton Metropolitan Airport, Castle Airport, Merced Municipal Airport, Hollister Municipal Airport, Livermore Municipal Airport, Sacramento Mather Airport, Norman Y. Mineta San José International Airport, and Sacramento Executive Airport.
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.