Weather in Seattle in September
Seattle, United States averages a high of 20.5°C (68.9°F) and low of 11.7°C (53.1°F) in September, with 8 rain days and 9.9 hours of daily sunshine. Travel score: 79/100 (Good). The best time to visit Seattle is July.
High
21°C69°F
Low
12°C53°F
🌧️
8
rain days
☀️
9.9
hrs/day sunshine
💧
76%
humidity
79— Good
September in Seattle is mild and occasionally wet — good for most activities.
What are the average temperatures in Seattle?
How much does it rain in Seattle in September?
Seattle receives an average of 63mm of rainfall across 8 rainy days in September. The annual total is 1249.4mm.
What should I pack for Seattle in September?
Essentials
👟
Comfortable walking shoes
Essential for exploring the city
🧥
Mix of light and warm layers
Mild temperatures around 21°C
🧴
Sunscreen SPF 30+
10 hours of sunshine daily
🕶️
Sunglasses
Protect your eyes from bright sun
Recommended
🧥
Light rain jacket
Some rainy days expected (8 days)
☔
Umbrella
Be prepared for occasional showers
Traveling to United States in September?
Don't let a public holiday surprise you — restaurants, shops, and attractions may be closed.
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Data based on 1994–2024 averages · Last updated: 2024-12-31