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.
|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).
|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.
|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.
|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.
|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 Time||1 am||4 am||7 am||10 am||1 pm||4 pm||7 pm||10 pm|
|9.5 mph||January wind speed average||15.3 kph|
January is one of the windiest months in Seattle.
|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.