San Francisco climate: monthly averages: annual mean temperature 13.6 C; warmest month Sep (17.6 C); coldest month Jan (9.3 C).
Annual mean temperature: 13.6 C
Warmest month: Sep (17.6 C)
Coldest month: Jan (9.3 C)
Wettest month: Dec (4.46 mm/day)
All-time record high: 39.0 C
All-time record low: -0.8 C
This is the short version of San Francisco climate: monthly averages, with the monthly detail underneath. The gap between Jan and Sep is 8.3 C here: 9.3 C against 17.6 C. Precipitation peaks in Dec (4.46 mm/day) and bottoms out in Jul (0.04 mm/day), so a 111.5x difference between the two. Taken together that is roughly 589 mm of rain a year for the grid cell. The same build that regenerates the sitemap refreshes these values, and unchanged pages are left untouched. Scroll for the month-by-month figures, or jump to a neighbouring location from the links below.
Annual mean temperature 13.6 C
Warmest month Sep (17.6 C)
Coldest month Jan (9.3 C)
Wettest month Dec (4.46 mm/day)
All-time record high 39.0 C
All-time record low -0.8 C
Annual precipitation 584 mm / year
Coordinates 37.77493, -122.41942
Population 827,526
Average monthly temperature and rainfall in San Francisco
Month
Mean temp (C)
Rain (mm/day)
Record high (C)
Record low (C)
Jan
9.3
3.23
21.0
-0.7
Feb
10.3
3.62
22.2
1.1
Mar
11.4
2.66
24.7
1.3
Apr
12.2
1.39
29.6
3.1
May
14.0
0.59
33.7
5.0
Jun
16.0
0.20
34.3
7.5
Jul
16.8
0.04
33.4
9.5
Aug
17.3
0.04
35.5
9.9
Sep
17.6
0.12
39.0
9.3
Oct
15.8
0.95
34.3
5.8
Nov
12.4
2.06
27.7
0.7
Dec
9.6
4.46
20.1
-0.8
What the San Francisco climate table shows
Values are multi-decadal climatological averages for the 37.77493, -122.41942 grid cell, not a single year. Rain is the daily mean, so a value of 2.00 mm/day is about 60 mm across a 30-day month. Averages smooth over extremes, so use them for planning rather than for what to pack for next Tuesday.
Frequently asked questions
Does San get the same every year?
Close to it. Averaging decades smooths variation, so treat these as typical rather than guaranteed.