Climate and Average Weather Year Round at Sonoma County Airport California, United States
At Sonoma County Airport, the summers are long, warm, arid, and mostly clear and the winters are short, cold, wet, and partly cloudy. Over the course of the year, the temperature typically varies from 37°F to 84°F and is rarely below 28°F or above 96°F.
Based on the tourism score, the best time of year to visit Sonoma County Airport for warm-weather activities is from mid June to mid September.
Climate at Sonoma County Airport
The warm season lasts for 4.3 months, from June 2 to October 11, with an average daily high temperature above 78°F. The hottest month of the year at Sonoma County Airport is July, with an average high of 83°F and low of 52°F.
The cool season lasts for 2.5 months, from November 26 to February 13, with an average daily high temperature below 61°F. The coldest month of the year at Sonoma County Airport is December, with an average low of 38°F and high of 57°F.
Average High and Low Temperature at Sonoma County Airport
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 Sonoma County Airport
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
At Sonoma County Airport, the average percentage of the sky covered by clouds experiences extreme seasonal variation over the course of the year.
The clearer part of the year at Sonoma County Airport begins around May 17 and lasts for 5.2 months, ending around October 23.
The clearest month of the year at Sonoma County Airport is July, during which on average the sky is clear, mostly clear, or partly cloudy 90% of the time.
The cloudier part of the year begins around October 23 and lasts for 6.8 months, ending around May 17.
The cloudiest month of the year at Sonoma County Airport is February, during which on average the sky is overcast or mostly cloudy 57% of the time.
Cloud Cover Categories at Sonoma County Airport
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at Sonoma County Airport varies significantly throughout the year.
The wetter season lasts 5.4 months, from October 31 to April 12, with a greater than 18% chance of a given day being a wet day. The month with the most wet days at Sonoma County Airport is February, with an average of 9.3 days with at least 0.04 inches of precipitation.
The drier season lasts 6.6 months, from April 12 to October 31. The month with the fewest wet days at Sonoma County Airport is July, with an average of 0.2 days with at least 0.04 inches of precipitation.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone at Sonoma County Airport is February, with an average of 9.2 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 35% on February 20.
Daily Chance of Precipitation at Sonoma County Airport
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. Sonoma County Airport experiences extreme seasonal variation in monthly rainfall.
The rainy period of the year lasts for 8.2 months, from September 27 to June 2, with a sliding 31-day rainfall of at least 0.5 inches. The month with the most rain at Sonoma County Airport is February, with an average rainfall of 6.0 inches.
The rainless period of the year lasts for 3.8 months, from June 2 to September 27. The month with the least rain at Sonoma County Airport is July, with an average rainfall of 0.0 inches.
Average Monthly Rainfall at Sonoma County Airport
The length of the day at Sonoma County Airport varies significantly over the course of the year. In 2022, the shortest day is December 21, with 9 hours, 29 minutes of daylight; the longest day is June 21, with 14 hours, 51 minutes of daylight.
Hours of Daylight and Twilight at Sonoma County Airport
The earliest sunrise is at 5:46 AM on June 13, and the latest sunrise is 1 hour, 56 minutes later at 7:42 AM on November 5. The earliest sunset is at 4:50 PM on December 7, and the latest sunset is 3 hours, 49 minutes later at 8:39 PM on June 27.
Daylight saving time (DST) is observed at Sonoma County Airport during 2022, starting in the spring on March 13, lasting 7.8 months, and ending in the fall on November 6.
Sunrise & Sunset with Twilight and Daylight Saving Time at Sonoma County Airport
The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.
Solar Elevation and Azimuth at Sonoma County Airport
The figure below presents a compact representation of key lunar data for 2022. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.
Moon Rise, Set & Phases at Sonoma County Airport
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 Sonoma 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 at Sonoma County Airport
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
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 Sonoma County Airport experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 4.1 months, from March 10 to July 15, with average wind speeds of more than 7.3 miles per hour. The windiest month of the year at Sonoma County Airport is June, with an average hourly wind speed of 8.1 miles per hour.
The calmer time of year lasts for 7.9 months, from July 15 to March 10. The calmest month of the year at Sonoma County Airport is October, with an average hourly wind speed of 6.5 miles per hour.
Average Wind Speed at Sonoma County Airport
The predominant average hourly wind direction at Sonoma County Airport varies throughout the year.
The wind is most often from the west for 7.5 months, from March 3 to October 17, with a peak percentage of 78% on July 31. The wind is most often from the north for 4.5 months, from October 17 to March 3, with a peak percentage of 43% on January 1.
Wind Direction at Sonoma County Airport
Sonoma County Airport 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 water temperature experiences some seasonal variation over the course of the year.
The time of year with warmer water lasts for 2.5 months, from August 16 to October 31, with an average temperature above 55°F. The month of the year at Sonoma County Airport with the warmest water is September, with an average temperature of 56°F.
The time of year with cooler water lasts for 3.1 months, from March 27 to June 30, with an average temperature below 52°F. The month of the year at Sonoma County Airport with the coolest water is May, with an average temperature of 52°F.
Average Water Temperature at Sonoma County Airport
To characterize how pleasant the weather is at Sonoma County Airport throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Sonoma County Airport for general outdoor tourist activities is from mid June to mid September, with a peak score in the last week of July.
Tourism Score at Sonoma County Airport
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Sonoma County Airport for hot-weather activities is from mid June to early August, with a peak score in the first week of July.
Beach/Pool Score at Sonoma County Airport
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
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 at Sonoma County Airport typically lasts for 9.2 months (280 days), from around February 22 to around November 29, rarely starting before January 4 or after March 27, and rarely ending before November 8 or after December 30.
Time Spent in Various Temperature Bands and the Growing Season at Sonoma County Airport
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
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.
Based on growing degree days alone, the first spring blooms at Sonoma County Airport should appear around February 11, only rarely appearing before February 1 or after March 1.
Growing Degree Days at Sonoma County Airport
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 3.5 months, from May 9 to August 25, with an average daily incident shortwave energy per square meter above 7.2 kWh. The brightest month of the year at Sonoma County Airport is July, with an average of 8.3 kWh.
The darker period of the year lasts for 3.6 months, from November 3 to February 20, with an average daily incident shortwave energy per square meter below 3.3 kWh. The darkest month of the year at Sonoma County Airport is December, with an average of 2.1 kWh.
Average Daily Incident Shortwave Solar Energy at Sonoma County Airport
For the purposes of this report, the geographical coordinates of Sonoma County Airport are 38.509 deg latitude, -122.814 deg longitude, and 118 ft elevation.
The topography within 2 miles of Sonoma County Airport contains only modest variations in elevation, with a maximum elevation change of 105 feet and an average elevation above sea level of 99 feet. Within 10 miles contains only modest variations in elevation (1,719 feet). Within 50 miles contains very significant variations in elevation (4,813 feet).
The area within 2 miles of Sonoma County Airport is covered by cropland (68%), artificial surfaces (16%), and grassland (16%), within 10 miles by cropland (31%) and trees (25%), and within 50 miles by water (29%) and shrubs (25%).
This report illustrates the typical weather at Sonoma 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
Sonoma 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 Gnoss Field, Napa County Airport, Ukiah Municipal Airport, Nut Tree Airport, Travis Air Force Base, Buchanan Field Airport, Naval Air Station Alameda (historical), and Oakland International Airport.
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , 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 airports and weather stations are provided by AskGeo.com .
Maps are © OpenStreetMap contributors.
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.
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