October in Seattle averages a daily high of 16°C with nights around 8.3°C. Expect roughly 14.3 wet days totalling 84mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Seattle is July–August.
Based on SEATTLE BOEING FIELD, WA US (6.9km), 1995–2024. 26 years of October data.