March in Washington averages a daily high of 13.9°C with nights around 3.7°C. Expect roughly 10.3 wet days totalling 80.4mm. Generally workable, with some weather to plan around.
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 March data.