April in Sammamish averages a daily high of 14.9°C with nights around 5.9°C. Expect roughly 15.4 wet days totalling 70.1mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Sammamish is July–August.
Based on SEATTLE SAND POINT WEATHER FORECAST OFFICE, WA US (14km), 1995–2024. 29 years of April data.