Seattle weather in December
Long-run climate averages for Seattle, WA in December, plus what the forecast models say for the days ahead.
In December, Seattle averages 49°F by day and 40°F at night. It is the wettest month of the year here.
December in Seattle averages a daytime high of 49°F and an overnight low of 40°F, which reads as cool for this part of the world. It is among the three coldest months of the year here. It is also the wettest month, so build rain into any plan. Across the whole year Seattle sees roughly 43 inches of precipitation.
Climate averages tell you what to pack. They do not tell you what next Tuesday looks like - for that, see the live Seattle forecast with every model compared and how much they currently agree.
Seattle weather by month
what to expect in Seattle through the yearHere is Seattle's typical weather in each month: the average daytime high and overnight low in °F, how each month feels, and the wettest month marked. Use it to plan any trip to Seattle by season.
Bottom line: over the last 30 days the American model has been the most accurate forecast for Seattle, scoring 88/100 on our CheckWeather Score, ahead of the European at 86. See the full US accuracy scoreboard for exactly how every model is tested.
Common questions
How warm is Seattle in December?
Is December a good time to visit Seattle?
Does it rain a lot in Seattle in December?
Climate averages from ERA5 reanalysis. Model accuracy re-scored over a rolling 30 days. Page updated .