Seattle Weather in September – Average Temperature and Rainfall
- High
- 20.8°
- Low
- 12.9°
- Rainfall
- 63 mm
- Rainy season
- 10d
- max
- 32.4°
- min
- 6.6°
September
- Early
- 23.3° 9.0 mm
- Mid
- 20.2° 24.1 mm
- Late
- 18.8° 29.6 mm
Summary
The climate figures for Seattle are averaged from 2016–2025 observations (10 years). Annual rainfall averages about 1,178 mm.
The rainy season runs January–December. The wettest month is December with 183.9 mm across 19 rain days; the driest is July at just 13.6 mm.
The hottest month is August (average high 24.8°C) and the coolest is December (7.8°C).
The most comfortable time to visit Seattle is July — less rain and milder heat.
Monthly averages
Common questions
Will it rain in Seattle today?
No. The chance of rain today is only about 10%.
How hot is it in Seattle today?
Between 7°C and 13°C, with a felt maximum of 11°C.
What is the weather in Seattle tomorrow?
Tomorrow: heavy drizzle, 7–11°C, with a 87% chance of rain.