S
M
T
W
T
F
S
30
93°
57°
31
87°
54°
1
79°
55°
2
96°
57°
3
95°
64°
4
97°
61°
5
94°
65°
6
96°
63°
7
95°
64°
8
85°
58°
9
82°
53°
10
93°
51°
11
82°
54°
12
73°
54°
13
74°
47°
14
75°
56°
15
73°
46°
16
81°
53°
17
71°
54°
18
76°
57°
19
67°
53°
20
64°
51°
21
61°
53°
22
N/A
23
75°
58°
24
79°
55°
25
77°
51°
26
79°
54°
27
65°
51°
28
73°
58°
29
79°
51°
30
82°
49°
1
63°
47°
2
77°
47°
3
74°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Rapid City
Rapid City's September 2026 forecast shows daily high temperatures ranging from ° to °, with overnight lows between ° and °. The average high for September is ° with an average low of °. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Rapid City. See also: October | November | December.
