If you're looking for summer vibes, the best time to travel to Washington, D.C. (Arlington County), VA is in July, June and August, when the average temperature reaches 26.85 °C, while August, April and June are the 3 sunniest months of the year, with an average of 133.15 hours.
However, if you prefer colder temperatures, make sure you visit Washington, D.C. (Arlington County), VA during January, February or March to experience an average of 0.2 °C.
For those who don't care too much about temperatures, but want to avoid getting wet in the rain, it's important to avoid travelling during December, February and March, when the average precipitation in Washington, D.C. (Arlington County), VA is 12.58 mm, while the months of January, February and March are drier, with an average of 0 mm.