S
M
T
W
T
F
S
30
82°
67°
31
87°
68°
1
87°
69°
2
88°
71°
3
82°
70°
4
86°
69°
5
80°
63°
6
81°
58°
7
80°
55°
8
79°
62°
9
83°
63°
10
79°
55°
11
80°
56°
12
78°
55°
13
69°
47°
14
68°
41°
15
75°
56°
16
74°
53°
17
66°
59°
18
66°
55°
19
65°
58°
20
67°
55°
21
62°
50°
22
59°
46°
23
66°
49°
24
65°
50°
25
68°
49°
26
66°
52°
27
66°
53°
28
67°
51°
29
66°
49°
30
67°
50°
1
67°
51°
2
66°
44°
3
62°
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 59° to 68°, with overnight lows between 44° and 53°. The average high for September is 65° with an average low of 50°. 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.
