S
M
T
W
T
F
S
30
83°
69°
31
87°
71°
1
95°
77°
2
96°
78°
3
91°
77°
4
93°
76°
5
81°
72°
6
79°
68°
7
81°
64°
8
85°
65°
9
80°
71°
10
77°
64°
11
82°
60°
12
88°
66°
13
75°
56°
14
71°
53°
15
85°
67°
16
76°
64°
17
80°
66°
18
72°
65°
19
70°
63°
20
69°
61°
21
66°
59°
22
63°
57°
23
68°
60°
24
70°
60°
25
64°
56°
26
69°
51°
27
72°
49°
28
73°
52°
29
78°
54°
30
70°
60°
1
70°
56°
2
65°
51°
3
68°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in O'Hare
O'Hare's September 2026 forecast shows daily high temperatures ranging from 65° to 70°, with overnight lows between 51° and 56°. The average high for September is 68° with an average low of 53°. 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 O'Hare. See also: October | November | December.
