Will I be hot?
Will I be hot in Jacksonville in January?
Verdict
No — No, comfortable.
Highs cap at 65°F — no heat-management gear needed.
Day vs. night
Day
65°F
Comfortable
A T-shirt and a light overshirt is enough.
Night
43°F
Cold
Cold enough that a hat and gloves become mandatory.
Why
Jacksonville in January averages highs of 65°F, lows of 43°F, 9 rainy days.
Temperature is comfortable across the day; pack for style and weather resistance, not heat management.