S
M
T
W
T
F
S
29
42°
24°
30
43°
25°
1
44°
23°
2
40°
22°
3
41°
24°
4
44°
25°
5
43°
18°
6
44°
12°
7
36°
17°
8
33°
14°
9
36°
16°
10
37°
14°
11
30°
23°
12
34°
18°
13
38°
18°
14
37°
11°
15
34°
12°
16
31°
12°
17
33°
17°
18
31°
17°
19
39°
22°
20
38°
18°
21
37°
12°
22
32°
9°
23
29°
11°
24
31°
17°
25
34°
19°
26
38°
13°
27
36°
9°
28
33°
8°
29
28°
10°
30
30°
10°
31
35°
5°
1
33°
5°
2
26°
20°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Custer
Custer's December 2026 forecast shows daily high temperatures ranging from 26° to 44°, with overnight lows between 5° and 25°. The average high for December is 36° with an average low of 16°. 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 Custer. See also: January | February | March.