S
M
T
W
T
F
S
30
81°
61°
31
81°
61°
1
80°
60°
2
77°
60°
3
80°
59°
4
80°
60°
5
79°
59°
6
80°
60°
7
81°
60°
8
80°
59°
9
76°
58°
10
77°
58°
11
79°
59°
12
77°
58°
13
79°
56°
14
67°
45°
15
67°
52°
16
70°
52°
17
69°
50°
18
67°
48°
19
72°
49°
20
75°
53°
21
75°
53°
22
74°
50°
23
73°
42°
24
68°
42°
25
68°
51°
26
70°
51°
27
69°
41°
28
69°
40°
29
63°
45°
30
65°
49°
1
65°
48°
2
68°
50°
3
71°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Sun Prairie
Sun Prairie's September 2026 forecast shows daily high temperatures ranging from 63° to 81°, with overnight lows between 40° and 61°. The average high for September is 73° 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 Sun Prairie. See also: October | November | December.
