April in Seattle averages a daily high of 15°C with nights around 6.3°C. Expect roughly 14.2 wet days totalling 61.2mm. 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 April data.