March in Sammamish averages a daily high of 12.1°C with nights around 4°C. Expect roughly 18.4 wet days totalling 98.3mm. 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 March data.