March in Seattle averages a daily high of 12.2°C with nights around 4.2°C. Expect roughly 17 wet days totalling 92.3mm. Demanding conditions — pack for it and plan indoor options.
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 March data.