S
M
T
W
T
F
S
30
75°
60°
31
75°
61°
1
77°
61°
2
79°
54°
3
78°
50°
4
70°
55°
5
70°
60°
6
78°
53°
7
74°
51°
8
68°
50°
9
69°
55°
10
70°
58°
11
69°
57°
12
77°
57°
13
76°
55°
14
74°
49°
15
66°
48°
16
65°
51°
17
67°
48°
18
65°
46°
19
66°
43°
20
64°
43°
21
63°
49°
22
64°
51°
23
69°
45°
24
67°
51°
25
69°
52°
26
65°
53°
27
71°
51°
28
71°
45°
29
70°
46°
30
60°
47°
1
63°
48°
2
69°
50°
3
63°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Fond du Lac
Fond du Lac's September 2026 forecast shows daily high temperatures ranging from 60° to 79°, with overnight lows between 43° and 61°. The average high for September is 70° with an average low of 52°. 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 Fond du Lac. See also: October | November | December.