S
M
T
W
T
F
S
30
83°
70°
31
89°
70°
1
96°
73°
2
96°
77°
3
86°
75°
4
92°
73°
5
80°
70°
6
79°
67°
7
80°
70°
8
87°
69°
9
87°
65°
10
80°
60°
11
77°
61°
12
79°
61°
13
82°
63°
14
80°
62°
15
81°
62°
16
75°
55°
17
78°
60°
18
71°
59°
19
75°
60°
20
76°
59°
21
75°
59°
22
74°
57°
23
71°
57°
24
73°
55°
25
76°
57°
26
76°
52°
27
65°
47°
28
63°
45°
29
64°
48°
30
64°
45°
1
63°
47°
2
66°
53°
3
65°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Winnetka
Winnetka's September 2026 forecast shows daily high temperatures ranging from 63° to 92°, with overnight lows between 45° and 75°. The average high for September is 75° with an average low of 59°. 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 Winnetka. See also: October | November | December.
