Will I be hot?
Will I be hot in San Antonio in January?
Verdict
No — No, comfortable.
Highs cap at 62°F — no heat-management gear needed.
Day vs. night
Day
62°F
Comfortable
A T-shirt and a light overshirt is enough.
Night
40°F
Cold
Cold enough that a hat and gloves become mandatory.
Why
San Antonio in January averages highs of 62°F, lows of 40°F, 8 rainy days.
Temperature is comfortable across the day; pack for style and weather resistance, not heat management.