August in Seattle averages a daily high of 25.1°C with nights around 14.8°C. Expect roughly 3.9 wet days totalling 17mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Seattle is July–August.
Based on SEATTLE BOEING FIELD, WA US (6.9km), 1995–2024. 25 years of August data.