May in Bellevue averages a daily high of 18.5°C with nights around 9.1°C. Expect roughly 12.3 wet days totalling 56.6mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Bellevue is July–August.
Based on SEATTLE SAND POINT WEATHER FORECAST OFFICE, WA US (9.5km), 1995–2024. 29 years of May data.