January in Rockville averages a daily high of 7°C with nights around -3.1°C. Expect roughly 9.7 wet days totalling 79.7mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Rockville is April–May.
Based on DALECARLIA RESERVOIR, MD US (16.5km), 1995–2024. 29 years of January data.