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Average Weather in Folsom California, United States

In Folsom, the summers are hot, arid, and mostly clear and the winters are 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 32°F or above 103°F.


The hot season lasts for 3.4 months, from June 8 to September 21, with an average daily high temperature above 86°F. The hottest day of the year is July 19, with an average high of 95°F and low of 63°F.

The cool season lasts for 3.0 months, from November 21 to February 22, 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 53°F.

Average High and Low Temperature

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 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

Average Hourly Temperature in FolsomJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMhotcoldcoolwarmvery coldcomfortable
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.


In Folsom, 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 in Folsom begins around May 20 and lasts for 5.1 months, ending around October 23. On July 29, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 91% of the time, and overcast or mostly cloudy 9% of the time.

The cloudier part of the year begins around October 23 and lasts for 6.9 months, ending around May 20. On February 6, the cloudiest day of the year, the sky is overcast or mostly cloudy 57% of the time, and clear, mostly clear, or partly cloudy 43% of the time.

Cloud Cover Categories

Cloud Cover Categories in FolsomclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jul 2991%Jul 2991%Feb 643%Feb 643%May 2067%May 2067%Oct 2367%Oct 2367%clearovercastpartly cloudymostly clear
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.


A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Folsom varies significantly throughout the year.

The wetter season lasts 5.4 months, from October 30 to April 12, with a greater than 16% chance of a given day being a wet day. The chance of a wet day peaks at 32% on February 20.

The drier season lasts 6.5 months, from April 12 to October 30. The smallest chance of a wet day is 0% on July 19.

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 32% on February 20.

Daily Chance of Precipitation

Daily Chance of Precipitation in FolsomwetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Feb 2032%Feb 2032%Jul 190%Jul 190%Jan 128%Jan 128%Oct 3016%Oct 3016%Apr 1216%Apr 1216%rain
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).


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. Folsom experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 8.1 months, from September 26 to May 30, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around February 16, with an average total accumulation of 4.6 inches.

The rainless period of the year lasts for 3.9 months, from May 30 to September 26. The least rain falls around July 30, with an average total accumulation of 0.0 inches.

Average Monthly Rainfall

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.


The length of the day in Folsom varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 28 minutes of daylight; the longest day is June 20, with 14 hours, 53 minutes of daylight.

Hours of Daylight and Twilight

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 earliest sunrise is at 5:39 AM on June 13, and the latest sunrise is 1 hour, 56 minutes later at 7:35 AM on November 4. The earliest sunset is at 4:43 PM on December 7, and the latest sunset is 3 hours, 50 minutes later at 8:33 PM on June 27.

Daylight saving time (DST) is observed in Folsom 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

Sunrise & Sunset with Twilight and Daylight Saving Time in FolsomJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 135:39 AMJun 135:39 AM8:33 PMJun 278:33 PMJun 27Dec 74:43 PMDec 74:43 PM7:35 AMNov 47:35 AMNov 4Mar 12DSTMar 12DSTDSTNov 5DSTNov 5daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2017. 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. The transitions to and from daylight saving time are indicated by the 'DST' labels.


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 in Folsom, 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

Humidity Comfort Levels in FolsomJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jan 270%Jan 270%Sep 150%Sep 150%comfortablecomfortabledrydry
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.


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 Folsom experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 4.7 months, from November 19 to April 9, with average wind speeds of more than 6.0 miles per hour. The windiest day of the year is February 20, with an average hourly wind speed of 6.6 miles per hour.

The calmer time of year lasts for 7.3 months, from April 9 to November 19. The calmest day of the year is October 5, with an average hourly wind speed of 5.3 miles per hour.

Average Wind Speed

Average Wind Speed in FolsomwindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph1 mph2 mph3 mph4 mph5 mph6 mph7 mph8 mph9 mph10 mph11 mph12 mphFeb 206.6 mphFeb 206.6 mphOct 55.3 mphOct 55.3 mphNov 196.0 mphNov 196.0 mphApr 96.0 mphApr 96.0 mph
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in Folsom is from the south throughout the year.

Wind Direction

Wind Direction in FolsomJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%southeastwestnorth
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 experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.4 months, from May 10 to August 24, with an average daily incident shortwave energy per square meter above 7.2 kWh. The brightest day of the year is July 1, with an average of 8.5 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 day of the year is December 21, with an average of 2.0 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in FolsombrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWh10 kWhJul 18.5 kWhJul 18.5 kWhDec 212.0 kWhDec 212.0 kWhMay 107.2 kWhMay 107.2 kWhAug 247.2 kWhAug 247.2 kWhNov 33.3 kWhNov 33.3 kWhFeb 203.3 kWhFeb 203.3 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.


For the purposes of this report, the geographical coordinates of Folsom are 38.678 deg latitude, -121.176 deg longitude, and 279 ft elevation.

The topography within 2 miles of Folsom contains only modest variations in elevation, with a maximum elevation change of 397 feet and an average elevation above sea level of 267 feet. Within 10 miles contains only modest variations in elevation (1,476 feet). Within 50 miles contains very significant variations in elevation (7,625 feet).

The area within 2 miles of Folsom is covered by artificial surfaces (83%) and cropland (12%), within 10 miles by artificial surfaces (42%) and grassland (35%), and within 50 miles by cropland (31%) and grassland (25%).

Data Sources

This report illustrates the typical weather in Folsom, 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 5 weather stations near enough to contribute to our estimation of the temperature and dew point in Folsom.

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

The stations contributing to this reconstruction are: Sacramento Mather Airport (40%, 16 kilometers, southwest); Mc Clellan Airfield (31%, 20 kilometers, west); Lincoln Regional Airport (17%, 30 kilometers, northwest); Auburn Municipal Airport (8%, 32 kilometers, north); and Placerville Airport (4.0%, 37 kilometers, east).

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.


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.