S
M
T
W
T
F
S
26
85°
59°
27
85°
66°
28
76°
57°
29
80°
51°
30
86°
55°
31
82°
63°
1
80°
63°
2
78°
57°
3
79°
53°
4
86°
53°
5
78°
64°
6
81°
60°
7
85°
59°
8
78°
58°
9
75°
55°
10
79°
57°
11
82°
54°
12
81°
58°
13
82°
56°
14
80°
55°
15
86°
52°
16
82°
58°
17
78°
52°
18
82°
53°
19
75°
51°
20
79°
46°
21
74°
55°
22
73°
61°
23
66°
55°
24
71°
53°
25
78°
62°
26
74°
62°
27
72°
53°
28
73°
56°
29
78°
63°
30
77°
64°
31
74°
58°
1
73°
58°
2
73°
54°
3
72°
57°
4
76°
56°
5
75°
58°
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 78°, with overnight lows between 53° and 64°. The average high for August is 74° with an average low of 58°. 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.
