Typical Run Score
84
Great
Seattle · December
Running in Seattle in December
Typical December running conditions in Seattle — and a live Run Score so you can see how today compares with the norm.
Avg temperature
42°F
Cool
Avg dew point
38°F
Comfortable
Best window
11 AM–6 PM
Local time
Seattle · today vs the December normTemperature · dew point · wind · timing
How December compares in Seattle
December ranks 8th of 12 months for running in Seattle, with a typical daytime Run Score of 84 (Great). For reference, the best month is May (score 92) and the hardest is July (score 76). The kindest window in December is typically 11 AM–6 PM. Precipitation falls in roughly 33% of hours this month. Use the live tool below to see how today actually compares with the December norm.
Running weather in nearby cities
Same engine, different climate. Check the best time to run in these cities too.
Running in Seattle in December: FAQ
Is it good to run in Seattle in December?
Yes — it's one of the better months to run here. The typical daytime Run Score is 84 (Great), with temperatures around 42°F (6°C) and comfortable dew points. The best window is usually 11 AM–6 PM.
How hot is it for running in Seattle in December?
Typical temperatures average 42°F (6°C) (Cool) with dew points near 38°F. Dew point — not the thermometer — usually decides how hard the run feels.
What is a good Run Score?
Scores run 0–100. 97+ is Perfect, 80–96 is Great — conditions are actively working in your favour. 65–79 (Good) is solid. 45–64 (Mixed) means at least one factor — usually heat or dew point — is taxing you. Below 45 (Poor), expect a noticeably harder effort or hold back for safety.
Why does dew point matter more than temperature?
Your body cools by evaporating sweat. When the dew point climbs above roughly 60°F, the air is too saturated for sweat to evaporate efficiently, so heat builds up even if the thermometer looks reasonable. That's why a 70°F muggy morning can feel harder than a dry 80°F afternoon.
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