S
M
T
W
T
F
S
26
104°
72°
27
103°
71°
28
99°
67°
29
100°
67°
30
88°
66°
31
87°
60°
1
99°
74°
2
100°
68°
3
86°
52°
4
77°
54°
5
82°
61°
6
90°
64°
7
94°
68°
8
97°
67°
9
91°
66°
10
84°
65°
11
86°
64°
12
84°
63°
13
83°
60°
14
84°
61°
15
89°
67°
16
89°
66°
17
79°
65°
18
82°
64°
19
82°
65°
20
83°
66°
21
87°
65°
22
82°
64°
23
83°
64°
24
86°
63°
25
79°
56°
26
76°
57°
27
82°
62°
28
87°
64°
29
87°
66°
30
88°
65°
31
87°
64°
1
86°
65°
2
87°
64°
3
86°
63°
4
80°
62°
5
84°
63°
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 76° to 100°, with overnight lows between 52° and 74°. The average high for August is 86° with an average low of 64°. 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.
