San Francisco Weather in May

San Francisco, California enjoys sunny and dry weather during May along with mild temperatures.

This page gives detailed information on the typical May temperature, precipitation, sun, humidity, wind and storms for San Francisco. The temperature, rainfall, sunshine and wind speed numbers here are historical averages based on climate data gathered in downtown San Francisco near the corner of Buchanan and Hermann Streets. The other measurements are averages at San Francisco International Airport, located south of the city center.

Temperature Weather iconTemperature

64 °F May average high 18 °C
51 °F May average low 11 °C
26 days 60 °F max. or more (16 °C)
11 days 50 °F min. or less (10 °C)

Usually every day during May the temperature rises to over 50 degrees Fahrenheit (10 degrees Celsius) in San Francisco. The city averages 5 days this month when the thermometer reaches into the 70s °F (over 21 °C). Temperatures above 90 °F (32 °C) rarely happen during May.

The thermometer dips to 60 °F (16 °C) or below every night this month. But May does not normally get as cold as 40 °F (4 °C).

Rainy Weather iconRain

0.7 in total precipitation 18 mm
4 days of rain

Half the time, San Francisco receives 0.1 to 1.0 inches (2 to 25 mm) of rainfall in May. One in four years has drier weather, while another one in four is wetter.

Sunny Weather iconSun

72 % sunshine
14 days clear skies

The sun's rays reach the ground in San Francisco during 72 percent of daylight hours on average in May, for a total of 318 hours in the month. Typically on 14 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in May at San Francisco lasts for 14 hours and 13 minutes a day on average. The shortest day of the month is the 1st with 13 hours and 47 minutes of daylight. By the end of the month, the days have lengthened to 14:36 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

71 % May average humidity

The relative humidity in San Francisco during May usually peaks at 83 percent in the morning then drops to 56 percent by early afternoon.

Local Time1 am4 am7 am10 am1 pm4 pm7 pm10 pm
Humidity % 82 83 78 63 56 59 71 78

Windy Weather iconWind

10.4 mph May wind speed average 16.7 kph

May is windier than most other months in San Francisco.

Stormy Weather iconStorms

0 days rainfall of 0.5 inches (13 mm) or more
0 days with thunderstorms in May

Once every few years, San Francisco receives half an inch (13 mm) or more of rain in one day during May.

San Francisco has a May thunderstorm just once a decade on average.


The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals.

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