May in Washington averages a daily high of 24.4°C with nights around 14.3°C. Expect roughly 12 wet days totalling 105.1mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Washington is April–May.
Based on WASHINGTON REAGAN NATIONAL AIRPORT, VA US (5.3km), 1995–2024. 30 years of May data.