S
M
T
W
T
F
S
29
43°
20°
30
39°
26°
1
43°
28°
2
47°
28°
3
48°
27°
4
47°
28°
5
41°
22°
6
38°
23°
7
40°
23°
8
43°
19°
9
36°
12°
10
31°
11°
11
31°
15°
12
32°
10°
13
30°
7°
14
28°
15°
15
30°
12°
16
32°
12°
17
31°
24°
18
37°
27°
19
44°
27°
20
45°
24°
21
42°
18°
22
36°
12°
23
29°
7°
24
28°
10°
25
28°
19°
26
34°
23°
27
43°
17°
28
42°
18°
29
39°
25°
30
42°
24°
31
43°
22°
1
41°
20°
2
37°
19°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Rapid City
Rapid City's December 2026 forecast shows daily high temperatures ranging from 28° to 48°, with overnight lows between 7° and 28°. The average high for December is 38° 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 Rapid City. See also: January | February | March.
