S
M
T
W
T
F
S
29
47°
29°
30
47°
29°
1
43°
26°
2
46°
23°
3
41°
28°
4
42°
33°
5
49°
39°
6
54°
36°
7
56°
32°
8
55°
29°
9
43°
31°
10
48°
34°
11
47°
33°
12
49°
27°
13
46°
24°
14
38°
19°
15
37°
25°
16
37°
29°
17
38°
32°
18
40°
33°
19
45°
37°
20
53°
32°
21
54°
25°
22
46°
29°
23
43°
31°
24
45°
30°
25
42°
30°
26
44°
19°
27
40°
17°
28
39°
20°
29
34°
12°
30
34°
13°
31
33°
12°
1
29°
17°
2
34°
21°
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 56°, with overnight lows between 12° and 39°. The average high for December is 43° with an average low of 27°. 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.
