S
M
T
W
T
F
S
30
90°
70°
31
88°
67°
1
91°
67°
2
91°
68°
3
93°
70°
4
93°
69°
5
90°
73°
6
82°
68°
7
87°
67°
8
79°
68°
9
83°
57°
10
84°
60°
11
84°
59°
12
77°
53°
13
62°
59°
14
78°
56°
15
67°
52°
16
66°
52°
17
73°
55°
18
69°
54°
19
73°
52°
20
72°
53°
21
71°
53°
22
72°
50°
23
75°
48°
24
79°
56°
25
80°
56°
26
79°
56°
27
78°
55°
28
76°
55°
29
76°
54°
30
75°
51°
1
67°
52°
2
76°
51°
3
75°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in North Sioux City
North Sioux City's September 2026 forecast shows daily high temperatures ranging from 62° to 84°, with overnight lows between 48° and 60°. The average high for September is 74° with an average low of 54°. 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 North Sioux City. See also: October | November | December.
