Pack or skip
Thermal underwear for Pittsburgh in December
Verdict
Pack it
Lows around 25°F — thermals are the difference between a walk and a march.
Why
Pittsburgh in December averages highs of 39°F, lows of 25°F, 15 rainy days.
That climate means thermal underwear earns its space in the bag. Lows around 25°F — thermals are the difference between a walk and a march.