S
M
T
W
T
F
S
29
49°
26°
30
47°
26°
1
45°
22°
2
37°
24°
3
43°
25°
4
48°
25°
5
50°
22°
6
41°
19°
7
39°
17°
8
35°
18°
9
41°
21°
10
42°
19°
11
39°
25°
12
41°
10°
13
42°
9°
14
31°
14°
15
34°
10°
16
32°
12°
17
31°
19°
18
34°
23°
19
36°
19°
20
36°
19°
21
39°
22°
22
Hist. Avg.
34°
14°
23
Hist. Avg.
34°
14°
24
Hist. Avg.
34°
14°
25
Hist. Avg.
34°
14°
26
Hist. Avg.
34°
14°
27
Hist. Avg.
34°
14°
28
Hist. Avg.
34°
14°
29
Hist. Avg.
34°
14°
30
Hist. Avg.
34°
14°
31
Hist. Avg.
34°
14°
1
Hist. Avg.
34°
14°
2
Hist. Avg.
34°
14°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
December Weather in Casper
Casper's December 2026 forecast shows daily high temperatures ranging from 31° to 50°, with overnight lows between 9° and 26°. The average high for December is 40° with an average low of 19°. 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 Casper. See also: January | February | March.
