S
M
T
W
T
F
S
29
43°
33°
30
46°
25°
1
45°
27°
2
39°
23°
3
45°
20°
4
32°
19°
5
31°
20°
6
31°
20°
7
34°
23°
8
36°
25°
9
35°
25°
10
34°
24°
11
31°
20°
12
30°
22°
13
30°
19°
14
31°
15°
15
28°
12°
16
26°
11°
17
24°
23°
18
33°
24°
19
35°
27°
20
40°
24°
21
39°
27°
22
38°
29°
23
40°
27°
24
40°
24°
25
37°
22°
26
34°
24°
27
35°
26°
28
37°
28°
29
39°
27°
30
40°
26°
31
39°
22°
1
37°
20°
2
34°
19°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in St. Louis
St. Louis's December 2026 forecast shows daily high temperatures ranging from 24° to 46°, with overnight lows between 11° and 33°. The average high for December is 36° with an average low of 23°. 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. Louis. See also: January | February | March.
