San Francisco Weather in January

January has the coldest weather of the year for San Francisco, California. Yet the temperatures remain mild and well above freezing.

This page gives detailed information on the typical January 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

58 °F	January average high	14 °C
47 °F	January average low	8 °C

The first two weeks of January are among the chilliest of the year at San Francisco. These, along with the last week of December have daily highs averaging 57 degrees Fahrenheit (14 degrees Celsius) and the minimum averages 46 °F (8 °C).

12 days	60 °F max. or more (16 °C)
25 days	50 °F min. or less (10 °C)

Temperatures above 70 °F (21 °C) during January in San Francisco can occur, but don't happen every year .

The thermometer dips to 40 °F (4 °C) or below on an average of 2 nights this month. But January does not normally get cold enough for frost.

Rain

4.4 in	total precipitation	112 mm
11 days	of rain

Half the time, San Francisco receives 1.8 to 6.7 inches (46 to 170 mm) of rainfall in January. One in four years has drier weather, while another one in four is wetter. None of the precipitation falls as snow.

Sun

56 %	sunshine
9 days	clear skies

The sun's rays reach the ground in San Francisco during 56 percent of daylight hours on average in January, for a total of 172 hours in the month. Typically on 9 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in January at San Francisco lasts for 9 hours and 54 minutes a day on average. The shortest day of the month is the 1st with 9 hours and 37 minutes of daylight. By the end of the month, the days have lengthened to 10:18 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humidity

78 %	January average humidity

The relative humidity in San Francisco during January usually peaks at 86 percent in the morning then drops to 66 percent by late afternoon. This is the most humid month for San Francisco.

Local Time	1 am	4 am	7 am	10 am	1 pm	4 pm	7 pm	10 pm
Humidity %	84	86	86	79	68	66	77	81

Wind

6.7 mph

January wind speed average

10.8 kph

January is less windy than most other months in San Francisco.

Storms

3 days	rainfall of 0.5 inches (13 mm) or more
1 day	with thunderstorms in January

San Francisco averages one January thunderstorm every two years.