Will I be hot?
Will I be hot in San Francisco in December?
Verdict
No — No, comfortable.
Highs cap at 57°F — no heat-management gear needed.
Day vs. night
Day
57°F
Cool
Sweater weather with the option to add a light shell.
Night
46°F
Cool
You'll want a warm layer after sunset — not a heavy coat.
Why
San Francisco in December averages highs of 57°F, lows of 46°F, 11 rainy days.
Temperature is comfortable across the day; pack for style and weather resistance, not heat management.