S
M
T
W
T
F
S
29
57°
38°
30
58°
39°
1
58°
44°
2
59°
39°
3
60°
44°
4
61°
40°
5
59°
38°
6
57°
40°
7
58°
39°
8
62°
40°
9
62°
41°
10
61°
41°
11
61°
40°
12
62°
41°
13
62°
42°
14
61°
41°
15
62°
41°
16
61°
40°
17
61°
39°
18
62°
38°
19
61°
42°
20
61°
38°
21
57°
34°
22
55°
36°
23
52°
38°
24
54°
36°
25
53°
34°
26
51°
34°
27
53°
32°
28
53°
36°
29
54°
38°
30
55°
41°
31
56°
36°
1
58°
37°
2
56°
40°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Petaluma
Petaluma's December 2026 forecast shows daily high temperatures ranging from 51° to 62°, with overnight lows between 32° and 44°. The average high for December is 58° with an average low of 39°. 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 Petaluma. See also: January | February | March.
