S
M
T
W
T
F
S
31
75°
57°
1
85°
57°
2
89°
55°
3
73°
51°
4
77°
47°
5
67°
43°
6
73°
38°
7
85°
44°
8
90°
51°
9
85°
52°
10
92°
56°
11
100°
63°
12
89°
60°
13
86°
58°
14
68°
57°
15
88°
55°
16
70°
55°
17
65°
55°
18
66°
51°
19
69°
48°
20
75°
49°
21
82°
51°
22
73°
51°
23
73°
50°
24
81°
47°
25
84°
51°
26
87°
47°
27
83°
43°
28
92°
56°
29
86°
61°
30
90°
59°
1
86°
63°
2
97°
55°
3
99°
52°
4
74°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Rapid City
Rapid City's September 2025 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.
