S
M
T
W
T
F
S
30
77°
57°
31
79°
51°
1
81°
50°
2
73°
49°
3
70°
49°
4
71°
51°
5
71°
51°
6
75°
61°
7
80°
57°
8
82°
49°
9
77°
51°
10
73°
48°
11
73°
60°
12
75°
49°
13
78°
45°
14
70°
49°
15
71°
57°
16
75°
54°
17
78°
46°
18
70°
47°
19
70°
47°
20
75°
51°
21
69°
55°
22
69°
57°
23
78°
54°
24
78°
53°
25
74°
55°
26
77°
55°
27
76°
54°
28
77°
54°
29
75°
53°
30
76°
53°
1
76°
42°
2
75°
40°
3
62°
40°
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 62° to 82°, with overnight lows between 40° and 61°. The average high for September is 74° with an average low of 51°. 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.
