Seattle weather in December
December in Seattle: cold, soaked, with clean air — one of the weakest months to visit.
#12 of 12 months in Seattle · #532 of 604 destinations to visit in December · comfort 44/100 (tier F)
Updated June 2026 · climate normals from ERA5 reanalysis
Seattle climate normals — December
| Daytime high | 7°C / 45°F | 🧥 cold |
|---|---|---|
| Nighttime low | 3°C / 37°F | |
| Feels like (high) | 5°C / 41°F | |
| Rainfall | 203 mm / 8 in | ⛈ soaked |
| Rainy days | 19 days | |
| Humidity | 87% | 💦 very humid |
| Dew point | 2°C / 36°F | |
| Sunshine | 3.3 h/day | |
| Daylight | 8.5 h | |
| Wind | 15 km/h / 9 mph | |
| Snowfall | 6.9 cm / 2.7 in | |
| Air quality (US AQI) | 38 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Seattle in December — FAQ
- Is December a good time to visit Seattle?
- December in Seattle: cold, soaked, with clean air — one of the weakest months to visit. It ranks #12 of 12 months for Seattle on SeasonMap's comfort score (44/100).
- What is the weather like in Seattle in December?
- In December, Seattle averages a daily high of 7.1°C and a low of 2.5°C, with about 203.1 mm of rain over roughly 18.8 rainy days.
- What is the air quality in Seattle in December?
- Seattle has a mean US Air Quality Index of about 38 in December.
- Does it snow in Seattle in December?
- Seattle sees roughly 6.9 cm of snowfall in December.