December in Reston averages a daily high of 7.9°C with nights around -1.5°C. Expect roughly 10.2 wet days totalling 84.7mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Reston is August–October.
Based on VIENNA, VA US (9.6km), 1995–2024. 30 years of December data.