Will I be hot?
Will I be hot in Philadelphia in January?
Verdict
No — No, comfortable.
Highs cap at 40°F — no heat-management gear needed.
Day vs. night
Day
40°F
Cold
Direct sun feels cool at best; shade is jacket weather.
Night
25°F
Freezing
Deep freeze after sunset — every exposed step counts.
Why
Philadelphia in January averages highs of 40°F, lows of 25°F, 9 rainy days.
Temperature is comfortable across the day; pack for style and weather resistance, not heat management.