Pack or skip
Thermal underwear for Denver in December
Verdict
Pack it
Lows around 18°F — thermals are the difference between a walk and a march.
Why
Denver in December averages highs of 44°F, lows of 18°F, 6 rainy days.
That climate means thermal underwear earns its space in the bag. Lows around 18°F — thermals are the difference between a walk and a march.