S
M
T
W
T
F
S
26
90°
71°
27
87°
68°
28
80°
62°
29
80°
68°
30
81°
65°
31
80°
69°
1
79°
69°
2
85°
68°
3
83°
67°
4
79°
67°
5
79°
68°
6
86°
68°
7
80°
66°
8
79°
64°
9
77°
59°
10
77°
60°
11
78°
67°
12
82°
67°
13
80°
62°
14
77°
59°
15
77°
64°
16
78°
65°
17
77°
66°
18
78°
63°
19
79°
65°
20
83°
62°
21
76°
58°
22
77°
65°
23
83°
64°
24
87°
65°
25
86°
63°
26
86°
52°
27
75°
51°
28
74°
51°
29
75°
53°
30
77°
57°
31
79°
51°
1
81°
50°
2
73°
49°
3
70°
49°
4
71°
51°
5
71°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Sioux Falls
Sioux Falls's August 2026 forecast shows daily high temperatures ranging from 70° to 90°, with overnight lows between 49° and 71°. The average high for August is 79° with an average low of 61°. 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 Sioux Falls. See also: September | October | November.
