S
M
T
W
T
F
S
29
64°
50°
30
63°
49°
1
64°
48°
2
64°
50°
3
63°
47°
4
57°
43°
5
57°
46°
6
58°
49°
7
57°
44°
8
57°
46°
9
55°
49°
10
54°
42°
11
55°
40°
12
53°
40°
13
54°
41°
14
54°
40°
15
53°
41°
16
54°
41°
17
56°
42°
18
57°
41°
19
57°
46°
20
58°
43°
21
59°
44°
22
59°
44°
23
58°
40°
24
54°
39°
25
54°
38°
26
55°
38°
27
55°
40°
28
57°
41°
29
60°
42°
30
60°
41°
31
61°
47°
1
60°
48°
2
59°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in South San Francisco
South San Francisco's December 2026 forecast shows daily high temperatures ranging from 53° to 64°, with overnight lows between 38° and 50°. The average high for December is 58° with an average low of 44°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how December weather will actually feel in South San Francisco. See also: January | February | March.
