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Average Weather in San Andreas California, United States

In San Andreas, 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 92°F and is rarely below 32°F or above 100°F.

Climate Summary

91%91%43%43%clearovercastprecipitation: 4.6 inprecipitation: 4.6 in0.0 in0.0 inmuggy: 0%muggy: 0%0%0%drydrycoldcoolwarmhotwarmcoolcoldtourism score: 8.3tourism score: 8.30.50.5JanFebMarAprMayJunJulAugSepOctNovDec
Click on each chart for more information.

Based on the tourism score, the best time of year to visit San Andreas for warm-weather activities is from mid June to late September.

Temperature

The hot season lasts for 3.3 months, from June 9 to September 20, with an average daily high temperature above 84°F. The hottest day of the year is July 18, with an average high of 92°F and low of 66°F.

The cool season lasts for 3.2 months, from November 20 to February 25, with an average daily high temperature below 60°F. The coldest day of the year is December 30, 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 San AndreasJanFebMarAprMayJunJulAugSepOctNovDec12 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.

Clouds

In San Andreas, 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 San Andreas begins around May 17 and lasts for 5.2 months, ending around October 25. 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 25 and lasts for 6.8 months, ending around May 17. On February 21, 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 San AndreasclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%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 2143%Feb 2143%May 1767%May 1767%Oct 2568%Oct 2568%clearovercastpartly cloudymostly clearmostly cloudy
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.

Precipitation

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

The wetter season lasts 5.6 months, from October 30 to April 17, 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 6.4 months, from April 17 to October 30. The smallest chance of a wet day is 1% on July 30.

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 San AndreaswetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Feb 2032%Feb 2032%Jul 301%Jul 301%Jan 127%Jan 127%Oct 3016%Oct 3016%Apr 1716%Apr 1716%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).

Rainfall

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. San Andreas experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 8.3 months, from September 24 to June 2, 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 3.7 months, from June 2 to September 24. The least rain falls around August 3, 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.

Sun

The length of the day in San Andreas varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 30 minutes of daylight; the longest day is June 20, with 14 hours, 50 minutes of daylight.

Hours of Daylight and Twilight

Hours of Daylight and Twilight in San AndreasJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 7 minMar 2012 hr, 7 minMar 2014 hr, 50 minJun 2014 hr, 50 minJun 2012 hr, 8 minSep 2212 hr, 8 minSep 229 hr, 30 minDec 219 hr, 30 minDec 21nightnightday
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 5:38 AM on June 13, and the latest sunrise is 1 hour, 53 minutes later at 7:32 AM on November 4. The earliest sunset is at 4:42 PM on December 6, and the latest sunset is 3 hours, 48 minutes later at 8:29 PM on June 28.

Daylight saving time (DST) is observed in San Andreas 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 San AndreasJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 135:38 AMJun 135:38 AM8:29 PMJun 288:29 PMJun 28Dec 64:42 PMDec 64:42 PM7:32 AMNov 47:32 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.

Humidity

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 San Andreas, 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 San AndreasJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Feb 170%Feb 170%Sep 160%Sep 160%drydrycomfortablecomfortable
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.

Wind

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

The windier part of the year lasts for 4.1 months, from November 18 to March 22, with average wind speeds of more than 5.5 miles per hour. The windiest day of the year is February 4, with an average hourly wind speed of 6.1 miles per hour.

The calmer time of year lasts for 7.9 months, from March 22 to November 18. The calmest day of the year is September 18, with an average hourly wind speed of 4.9 miles per hour.

Average Wind Speed

Average Wind Speed in San AndreaswindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph1 mph2 mph3 mph4 mph5 mph6 mph7 mph8 mph9 mph10 mph11 mphFeb 46.1 mphFeb 46.1 mphSep 184.9 mphSep 184.9 mphNov 185.5 mphNov 185.5 mphMar 225.5 mphMar 225.5 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 San Andreas varies throughout the year.

The wind is most often from the south for 1.2 months, from February 17 to March 24, with a peak percentage of 36% on February 21. The wind is most often from the west for 6.7 months, from March 24 to October 15, with a peak percentage of 59% on July 14. The wind is most often from the east for 4.1 months, from October 15 to February 17, with a peak percentage of 45% on January 1.

Wind Direction

Wind Direction in San AndreasESWEJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%eastwestsouthnorth
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).

Best Time of Year to Visit

To characterize how pleasant the weather is in San Andreas 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 San Andreas for general outdoor tourist activities is from mid June to late September, with a peak score in the second week of August.

Tourism Score

Tourism Score in San Andreasbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468108.38.30.50.5 precipitationprecipitationcloudscloudstemperaturetemperaturetourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

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 San Andreas for hot-weather activities is from early July to late August, with a peak score in the third week of July.

Beach/Pool Score

Beach/Pool Score in San Andreasbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.46.40.00.0 precipitationprecipitationcloudscloudstemperaturetemperaturebeach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

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.

Growing Season

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 in San Andreas typically lasts for 10 months (313 days), from around February 2 to around December 12, rarely starting after March 12, or ending before November 16.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season in San Andreasgrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Feb 250%Feb 250%Dec 1250%Dec 1290%Mar 1290%Mar 1290%Nov 1690%Nov 1630%Jan 330%Jan 3Jul 17100%Jul 17100%warmhotcoldcoolvery coldcomfortablefreezing
The percentage of time spent in various temperature 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 black line is the percentage chance that a given day is within the growing season.

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 in San Andreas should appear around February 20, only rarely appearing before February 6 or after March 10.

Growing Degree Days

Growing Degree Days in San AndreasJanFebMarAprMayJunJulAugSepOctNovDec0°F500°F1,000°F1,500°F2,000°F2,500°F3,000°F3,500°F4,000°F4,500°FFeb 2088°FFeb 2088°FMay 26900°FMay 26900°FJul 61,800°FJul 61,800°FDec 314,514°FDec 314,514°F
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

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 3.5 months, from May 9 to August 24, with an average daily incident shortwave energy per square meter above 7.3 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 3.4 kWh. The darkest day of the year is December 21, with an average of 2.2 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in San AndreasbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWh10 kWhJun 278.5 kWhJun 278.5 kWhDec 212.2 kWhDec 212.2 kWhMay 97.3 kWhMay 97.3 kWhAug 247.3 kWhAug 247.3 kWhNov 33.4 kWhNov 33.4 kWhFeb 193.4 kWhFeb 193.4 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.

Topography

For the purposes of this report, the geographical coordinates of San Andreas are 38.196 deg latitude, -120.680 deg longitude, and 1,119 ft elevation.

The topography within 2 miles of San Andreas contains very significant variations in elevation, with a maximum elevation change of 869 feet and an average elevation above sea level of 1,048 feet. Within 10 miles contains very significant variations in elevation (2,585 feet). Within 50 miles contains large variations in elevation (10,322 feet).

The area within 2 miles of San Andreas is covered by grassland (64%) and shrubs (32%), within 10 miles by grassland (50%) and shrubs (31%), and within 50 miles by grassland (25%) and trees (25%).

Data Sources

This report illustrates the typical weather in San Andreas, 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 San Andreas.

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

The stations contributing to this reconstruction are: Placerville Airport (23%, 58 kilometers, north); Stockton Metropolitan Airport (26%, 59 kilometers, southwest); Modesto City-County Airport (23%, 68 kilometers, south); Sacramento Mather Airport (23%, 68 kilometers, northwest); and Bridgeport Sonora Junction (5%, 103 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.

Disclaimer

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.