S
M
T
W
T
F
S
26
86°
63°
27
80°
65°
28
80°
64°
29
81°
66°
30
83°
67°
31
84°
67°
1
89°
66°
2
82°
67°
3
82°
67°
4
83°
66°
5
88°
67°
6
86°
66°
7
78°
66°
8
80°
63°
9
78°
60°
10
78°
65°
11
82°
61°
12
80°
64°
13
78°
57°
14
78°
59°
15
79°
65°
16
79°
62°
17
83°
65°
18
84°
65°
19
84°
64°
20
78°
64°
21
77°
63°
22
81°
64°
23
85°
64°
24
87°
63°
25
87°
53°
26
86°
52°
27
76°
50°
28
75°
52°
29
76°
53°
30
77°
54°
31
83°
50°
1
76°
49°
2
72°
48°
3
71°
48°
4
73°
50°
5
74°
54°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Rapid City
Rapid City's August 2026 forecast shows daily high temperatures ranging from 71° to 89°, with overnight lows between 48° and 67°. The average high for August is 80° with an average low of 60°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Rapid City. See also: September | October | November.
