S
M
T
W
T
F
S
29
45°
29°
30
43°
28°
1
45°
33°
2
52°
30°
3
51°
31°
4
50°
37°
5
54°
38°
6
54°
34°
7
53°
24°
8
48°
27°
9
43°
30°
10
45°
34°
11
50°
34°
12
45°
35°
13
47°
36°
14
52°
33°
15
53°
25°
16
51°
25°
17
42°
22°
18
45°
23°
19
39°
26°
20
43°
27°
21
44°
34°
22
49°
31°
23
50°
27°
24
43°
22°
25
38°
23°
26
39°
27°
27
47°
30°
28
46°
22°
29
43°
23°
30
38°
27°
31
42°
13°
1
41°
11°
2
29°
14°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in St. Charles
St. Charles's December 2026 forecast shows daily high temperatures ranging from 29° to 54°, with overnight lows between 11° and 38°. The average high for December is 46° with an average low of 28°. 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 St. Charles. See also: January | February | March.
