Seattle Weather in January

Seattle, Washington already starts to emerge from winter weather during January as the days grow slightly warmer.

This page gives detailed information on the typical January temperature, precipitation, sun, humidity, wind and storms for Seattle. The weather measurements are averages based on climate data gathered at Seattle — Tacoma International Airport, located south of the city center.

Temperature Weather iconTemperature

48 °F January average high 9 °C
38 °F January average low 3 °C
12 days 50 °F max. or more (10 °C)
20 days 40 °F min. or less (4 °C)

The temperature rises nearly every day this month to over 40 degrees Fahrenheit (4 degrees Celsius) in Seattle. Temperatures of 60 °F (16 °C) and above are uncommon now and don't occur every year during January.

The thermometer dips to freezing or below on an average of 7 nights. But only in rare years does January get as cold as 20 °F (-8 °C).

Rainy Weather iconPrecipitation

5.8 in total precipitation 147 mm
19 days of rain or snowfall

Half the time, Seattle receives 4.2 to 7.1 inches (106 to 181 mm) of precipitation in January. One in four years has drier weather, while another one in four is wetter.

Snowy Weather iconSnow

1.8 in total snowfall 4 cm
1 day with new snow

Most years, Seattle receives no snow during January. In one out of four years, the city receives at least 2.4 inches (6 cm) of snow for the month.

Sunny Weather iconSun

28 % sunshine
3 days clear skies

The sun's rays reach the ground in Seattle during 28 percent of daylight hours on average in January, for a total of 78 hours in the month. Typically on 3 days this month the sky is mainly clear, with at most 30 percent cloud cover.

Sunlight in January at Seattle lasts for 8 hours and 57 minutes a day on average. The shortest day of the month is the 1st with 8 hours and 31 minutes of daylight. By the end of the month, the days have lengthened to 9:33 from sunrise to sunset. These durations can vary by a minute or two from year to year.

Humid Weather iconHumidity

78 % January average humidity

The relative humidity in Seattle during January usually peaks at 81 percent in the morning then drops to 74 percent by early afternoon.

Local Time1 am4 am7 am10 am1 pm4 pm7 pm10 pm
Humidity % 80 81 81 79 74 74 77 78

Windy Weather iconWind

9.5 mph January wind speed average 15.3 kph

January is one of the windiest months in Seattle.

Stormy Weather iconStorms

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

Seattle gets a January thunderstorm on an average of once every few 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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