August in Washington averages a daily high of 30.9°C with nights around 21.6°C. Expect roughly 9 wet days totalling 88.5mm. 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 August data.