December in Denver averages a daily high of 9°C with nights around -6.5°C. Expect roughly 3.9 wet days totalling 11.6mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Denver is September–October.
Based on DENVER WATER DEPARTMENT, CO US (2.3km), 1995–2024. 26 years of December data.