December weather forecast and climate
Colorado, USA

December brings the dreary cold of winter in Colorado with the average high temperatures in the 27°F (-2.8°C) to 45°F (7.2°C) range and the average low temperatures in the cold -4°F (-20°C) to 23°F (-5°C) range across the state. The average temperatures in Crested Butte in the west are between -4°F (-20°C) to 27°F (-2.8°C), while those in Fort Collins are between 15°F (-9.4°C) to 41°F (5°C).
Rain is negligible, but snowfall is substantial, particularly in the west and the mountainous parts of the state. Vail in the west registers 29.2" (742mm) of snow that is perfect for skiing. December sees an average of 10 sunny days with a reduced number of daylight hours. The skies are mostly clear, but the December sun is weak and radiates 60% to 70% heat of the normal.
Winter is an off-season that hardly draws tourists except for the visitors who like skiing and related adventure activities. Overall, the severe cold makes December the worst time to visit Colorado.