Average Weather in San Francisco Mexico
In San Francisco, the wet season is warm, oppressive, and overcast and the dry season is hot, humid, and partly cloudy. Over the course of the year, the temperature typically varies from 60°F to 89°F and is rarely below 55°F or above 92°F.
Based on the tourism score, the best time of year to visit San Francisco for warm-weather activities is from mid November to late April.
The temperature in San Francisco varies so little throughout the year that it is not entirely meaningful to discuss hot and cold seasons.
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
Goiânia, Brazil (4,129 miles away); Montes Claros, Brazil (4,439 miles); and Kilimatinde, Tanzania (9,262 miles) are the far-away foreign places with temperatures most similar to San Francisco (view comparison).
In San Francisco, 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 in San Francisco begins around November 6 and lasts for 6.4 months, ending around May 20. On February 24, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 72% of the time, and overcast or mostly cloudy 28% of the time.
The cloudier part of the year begins around May 20 and lasts for 5.6 months, ending around November 6. On September 14, the cloudiest day of the year, the sky is overcast or mostly cloudy 93% of the time, and clear, mostly clear, or partly cloudy 7% 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 in San Francisco varies very significantly throughout the year.
The wetter season lasts 4.6 months, from May 28 to October 14, with a greater than 36% chance of a given day being a wet day. The chance of a wet day peaks at 71% on September 13.
The drier season lasts 7.4 months, from October 14 to May 28. The smallest chance of a wet day is 1% on December 8.
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 71% on September 13.
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. San Francisco experiences extreme seasonal variation in monthly rainfall.
The rainy period of the year lasts for 6.5 months, from April 29 to November 14, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around September 7, with an average total accumulation of 8.2 inches.
The rainless period of the year lasts for 5.5 months, from November 14 to April 29. The least rain falls around April 2, with an average total accumulation of 0.1 inches.
Average Monthly Rainfall
The length of the day in San Francisco varies over the course of the year. In 2018, the shortest day is December 21, with 11 hours, 7 minutes of daylight; the longest day is June 21, with 13 hours, 9 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 6:32 AM on March 31, and the latest sunrise is 1 hour, 1 minute later at 7:33 AM on October 27. The earliest sunset is at 6:01 PM on November 23, and the latest sunset is 2 hours, 14 minutes later at 8:15 PM on July 6.
Daylight saving time (DST) is observed in San Francisco during 2018, starting in the spring on April 1, lasting 6.8 months, and ending in the fall on October 28.
Sunrise & Sunset with Twilight and Daylight Saving Time
San Francisco experiences extreme seasonal variation in the perceived humidity.
The muggier period of the year lasts for 7.8 months, from April 28 to December 20, during which time the comfort level is muggy, oppressive, or miserable at least 42% of the time. The muggiest day of the year is September 12, with muggy conditions 98% of the time.
The least muggy day of the year is March 12, with muggy conditions 23% of the time.
Humidity Comfort Levels
The average hourly wind speed in San Francisco experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 4.8 months, from January 26 to June 20, with average wind speeds of more than 5.6 miles per hour. The windiest day of the year is March 31, with an average hourly wind speed of 6.4 miles per hour.
The calmer time of year lasts for 7.2 months, from June 20 to January 26. The calmest day of the year is October 20, with an average hourly wind speed of 4.9 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in San Francisco is from the south throughout the year.
San Francisco 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 2.8 months, from June 19 to September 13, with an average temperature above 86°F. The day of the year with the warmest water is July 30, with an average temperature of 86°F.
The time of year with cooler water lasts for 3.2 months, from January 27 to May 1, with an average temperature below 83°F. The day of the year with the coolest water is March 19, with an average temperature of 82°F.
Average Water Temperature
Best Time of Year to Visit
To characterize how pleasant the weather is in San Francisco 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 Francisco for general outdoor tourist activities is from mid November to late April, with a peak score in the last week of February.
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 Francisco for hot-weather activities is from late March to late May, with a peak score in the first week of May.
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.
Temperatures in San Francisco are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.
Time Spent in Various Temperature Bands and the Growing Season
Growing Degree Days
The average daily incident shortwave solar energy experiences some seasonal variation over the course of the year.
The brighter period of the year lasts for 2.0 months, from March 5 to May 6, with an average daily incident shortwave energy per square meter above 6.6 kWh. The brightest day of the year is April 1, with an average of 7.1 kWh.
The darker period of the year lasts for 7.0 months, from June 14 to January 14, with an average daily incident shortwave energy per square meter below 5.1 kWh. The darkest day of the year is October 8, with an average of 4.7 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of San Francisco are 17.006 deg latitude, -99.283 deg longitude, and 2,103 ft elevation.
The topography within 2 miles of San Francisco contains large variations in elevation, with a maximum elevation change of 2,073 feet and an average elevation above sea level of 2,070 feet. Within 10 miles contains large variations in elevation (3,724 feet). Within 50 miles also contains extreme variations in elevation (9,685 feet).
The area within 2 miles of San Francisco is covered by cropland (72%) and trees (19%), within 10 miles by cropland (73%) and trees (22%), and within 50 miles by trees (36%) and cropland (29%).
This report illustrates the typical weather in San Francisco, 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 is only a single weather station, General Juan N. Álvarez International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of San Francisco.
At a distance of 57 kilometers from San Francisco, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.
The station records are corrected for the elevation difference between the station and San Francisco according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.
Time zones for aiports and weather stations are provided by AskGeo.com .