Will I be cold?
Will I be cold in Denver in December?
Verdict
Yes — Yes, cold.
Lows drop to 18°F on average — noticeably cold, especially after sundown. Big diurnal swing (26°F) — layers matter more than one warm coat.
Day vs. night
Day
44°F
Cold
Direct sun feels cool at best; shade is jacket weather.
Night
18°F
Freezing
Deep freeze after sunset — every exposed step counts.
Why
Denver in December averages highs of 44°F, lows of 18°F, 6 rainy days.
Plan for real winter kit — an insulated coat, warm hat, and gloves rather than a light jacket.
The day-to-night temperature swing is 26°F, which is the real story here — the average number hides how different midday and midnight feel.