S
M
T
W
T
F
S
30
98°
70°
31
93°
67°
1
90°
64°
2
92°
63°
3
94°
73°
4
99°
66°
5
92°
69°
6
83°
67°
7
86°
67°
8
86°
60°
9
81°
55°
10
85°
51°
11
88°
66°
12
73°
51°
13
71°
49°
14
67°
54°
15
73°
51°
16
74°
46°
17
73°
61°
18
70°
61°
19
68°
59°
20
62°
56°
21
58°
53°
22
61°
53°
23
64°
58°
24
63°
59°
25
66°
59°
26
71°
59°
27
75°
60°
28
73°
55°
29
68°
50°
30
70°
52°
1
69°
51°
2
67°
47°
3
65°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Sioux Falls
Sioux Falls's September 2026 forecast shows daily high temperatures ranging from 61° to 75°, with overnight lows between 47° and 60°. The average high for September is 68° with an average low of 55°. 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 Sioux Falls. See also: October | November | December.
