S
M
T
W
T
F
S
30
83°
70°
31
N/A
1
92°
77°
2
94°
74°
3
85°
74°
4
82°
72°
5
83°
69°
6
81°
66°
7
76°
64°
8
78°
65°
9
80°
64°
10
76°
62°
11
76°
58°
12
74°
58°
13
74°
61°
14
75°
57°
15
77°
62°
16
78°
62°
17
77°
61°
18
76°
62°
19
78°
63°
20
78°
62°
21
77°
62°
22
78°
61°
23
78°
61°
24
77°
60°
25
77°
61°
26
76°
59°
27
77°
60°
28
76°
60°
29
75°
59°
30
74°
58°
1
74°
57°
2
73°
57°
3
74°
56°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Wilmette
Wilmette's September 2026 forecast shows daily high temperatures ranging from 73° to 94°, with overnight lows between 56° and 77°. The average high for September is 78° with an average low of 63°. 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 Wilmette. See also: October | November | December.
