S
M
T
W
T
F
S
30
69°
47°
31
78°
43°
1
86°
46°
2
86°
49°
3
79°
53°
4
79°
48°
5
76°
47°
6
65°
52°
7
65°
52°
8
63°
44°
9
76°
55°
10
81°
46°
11
58°
41°
12
57°
41°
13
55°
38°
14
65°
40°
15
66°
41°
16
62°
40°
17
63°
44°
18
69°
48°
19
72°
49°
20
73°
51°
21
68°
39°
22
64°
47°
23
62°
43°
24
70°
45°
25
73°
47°
26
73°
47°
27
70°
46°
28
60°
36°
29
57°
33°
30
57°
36°
1
59°
36°
2
58°
37°
3
64°
43°
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 55° to 81°, with overnight lows between 33° and 55°. The average high for September is 65° with an average low of 43°. 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.
