July in Washington averages a daily high of 20.3°C with nights around 11.5°C. Expect roughly 13.9 wet days totalling 65.9mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Washington is June–September.
Based on DURHAM, UK (15.3km), 1995–2024. 28 years of July data.