S
M
T
W
T
F
S
30
83°
69°
31
87°
71°
1
94°
74°
2
94°
74°
3
91°
72°
4
91°
73°
5
88°
71°
6
81°
62°
7
76°
59°
8
77°
61°
9
76°
60°
10
76°
58°
11
75°
55°
12
76°
54°
13
76°
57°
14
75°
54°
15
78°
58°
16
78°
59°
17
77°
58°
18
77°
59°
19
78°
59°
20
79°
58°
21
79°
59°
22
78°
58°
23
78°
58°
24
77°
57°
25
78°
58°
26
78°
57°
27
77°
56°
28
76°
56°
29
75°
55°
30
75°
55°
1
74°
54°
2
75°
54°
3
75°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Oak Brook
Oak Brook's September 2026 forecast shows daily high temperatures ranging from 74° to 94°, with overnight lows between 53° and 74°. The average high for September is 79° with an average low of 60°. 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 Oak Brook. See also: October | November | December.
