San Diego Weather in January

Mild winter weather continues during January for San Diego, California with daytime temperatures in the mid 60s Fahrenheit (over 17 degrees Celsius).

This page gives detailed information on the typical January temperature, precipitation, sun, humidity, wind and storms for San Diego. The numbers here are historical averages based on climate data gathered at the San Diego International Airport, located on San Diego Bay near the city center.

Temperature Weather iconTemperature

66 °F January average high 19 °C
50 °F January average low 10 °C
28 days 60 °F max. or more (16 °C)
18 days 50 °F min. or less (10 °C)

Every day in January warms to over 50 °F (10 °C) in San Diego. The city averages just 1 day this month when the thermometer reaches into the 80s °F (over 26 °C). Temperatures above 90 °F (32 °C) are not expected here this time of year.

At night, the thermometer dips as low as 40 °F (4 °C) only rarely in January, and not every year. January does not normally get cold enough for frost.

Rainy Weather iconRain

2.0 in total precipitation 50 mm
7 days of rain

Half the time, San Diego receives 0.4 to 3 inches (9 to 77 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.

Sunny Weather iconSun

72 % sunshine
12 days clear skies

The sun's rays reach the ground in San Diego during 72 percent of daylight hours on average in January, for a total of 230 hours in the month. Typically on 12 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in January at San Diego lasts for 10 hours and 17 minutes a day on average. The shortest day of the month is the 1st with 10 hours and 3 minutes of daylight. By the end of the month, the days have lengthened to 10:37 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

63 % January average humidity

The relative humidity in San Diego during January usually peaks at 70 percent just after midnight then drops to 50 percent by early afternoon. January is the least humid month here.

Local Time1 am4 am7 am10 am1 pm4 pm7 pm10 pm
Humidity % 70 70 68 55 50 56 66 70

Windy Weather iconWind

6.0 mph January wind speed average 9.7 kph

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

Stormy Weather iconStorms

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

San Diego has a thunderstorm during January about once in five years.


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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