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.
Based on the tourism score, the best time of year to visit Folsom for warm-weather activities is from mid June to late September.
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 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
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
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 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
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 length of the day in Folsom varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 28 minutes of daylight; the longest day is June 21, with 14 hours, 53 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:39 AM on June 14, and the latest sunrise is 1 hour, 54 minutes later at 7:33 AM on November 3. 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 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.
Sunrise & Sunset with Twilight and Daylight Saving Time
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
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
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
The predominant average hourly wind direction in Folsom is from the south throughout the year.
Best Time of Year to Visit
To characterize how pleasant the weather is in Folsom 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 Folsom for general outdoor tourist activities is from mid June to late September, with a peak score in the first week of August.
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 Folsom for hot-weather activities is from late June to mid August, with a peak score in the third week of July.
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.
The growing season in Folsom typically lasts for 11 months (345 days), from around January 10 to around December 21, rarely starting after February 21, or ending before November 22.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Folsom should appear around February 16, only rarely appearing before February 5 or after March 1.
Growing Degree Days
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
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%).
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).
Time zones for aiports and weather stations are provided by AskGeo.com .