S
M
T
W
T
F
S
29
71°
49°
30
69°
46°
1
70°
38°
2
55°
35°
3
56°
35°
4
58°
46°
5
65°
39°
6
56°
35°
7
56°
36°
8
54°
34°
9
53°
33°
10
54°
32°
11
55°
34°
12
57°
35°
13
62°
41°
14
58°
37°
15
57°
35°
16
55°
38°
17
58°
35°
18
55°
32°
19
54°
30°
20
54°
32°
21
55°
33°
22
59°
32°
23
54°
32°
24
52°
31°
25
53°
31°
26
53°
32°
27
55°
32°
28
55°
33°
29
54°
32°
30
52°
32°
31
54°
30°
1
53°
30°
2
53°
35°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Riverside
Riverside's December 2026 forecast shows daily high temperatures ranging from 52° to 71°, with overnight lows between 30° and 49°. The average high for December is 57° with an average low of 35°. 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 Riverside. See also: January | February | March.
