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°
50°
16
69°
60°
17
73°
63°
18
76°
58°
19
70°
58°
20
65°
54°
21
69°
52°
22
69°
53°
23
71°
51°
24
72°
55°
25
75°
55°
26
76°
53°
27
73°
50°
28
72°
51°
29
70°
52°
30
67°
48°
1
73°
51°
2
68°
52°
3
74°
50°
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 65° to 76°, with overnight lows between 48° and 63°. The average high for September is 71° with an average low of 53°. 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.
