S
M
T
W
T
F
S
29
44°
31°
30
41°
32°
1
41°
34°
2
43°
21°
3
44°
18°
4
39°
17°
5
30°
16°
6
31°
17°
7
30°
16°
8
31°
14°
9
31°
13°
10
26°
15°
11
27°
15°
12
29°
16°
13
29°
18°
14
30°
23°
15
31°
24°
16
33°
20°
17
35°
22°
18
35°
28°
19
36°
27°
20
36°
26°
21
35°
23°
22
34°
26°
23
35°
19°
24
36°
20°
25
34°
25°
26
33°
19°
27
33°
15°
28
30°
14°
29
33°
21°
30
30°
12°
31
30°
22°
1
32°
22°
2
Hist. Avg.
33°
21°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in River Forest
River Forest's December 2026 forecast shows daily high temperatures ranging from 26° to 44°, with overnight lows between 12° and 34°. The average high for December is 34° with an average low of 21°. 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 River Forest. See also: January | February | March.
