S
M
T
W
T
F
S
29
46°
21°
30
34°
16°
1
35°
17°
2
43°
23°
3
47°
23°
4
43°
22°
5
38°
22°
6
36°
13°
7
31°
9°
8
43°
22°
9
47°
22°
10
46°
21°
11
46°
22°
12
45°
21°
13
46°
22°
14
43°
18°
15
42°
19°
16
43°
13°
17
41°
10°
18
34°
2°
19
33°
3°
20
27°
19°
21
38°
17°
22
40°
10°
23
40°
12°
24
38°
14°
25
41°
19°
26
40°
19°
27
45°
6°
28
39°
4°
29
32°
10°
30
32°
3°
31
30°
4°
1
27°
15°
2
37°
20°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Mount Rushmore Ut
Mount Rushmore Ut's December 2026 forecast shows daily high temperatures ranging from 27° to 47°, with overnight lows between 2° and 23°. The average high for December is 39° with an average low of 15°. 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 Mount Rushmore Ut. See also: January | February | March.