S
M
T
W
T
F
S
30
80°
61°
31
76°
62°
1
78°
62°
2
82°
58°
3
81°
52°
4
73°
53°
5
73°
61°
6
79°
56°
7
78°
52°
8
72°
55°
9
71°
56°
10
72°
59°
11
75°
58°
12
80°
59°
13
79°
58°
14
80°
53°
15
78°
51°
16
70°
53°
17
70°
49°
18
71°
48°
19
69°
45°
20
68°
45°
21
67°
47°
22
68°
54°
23
69°
47°
24
71°
53°
25
73°
54°
26
70°
55°
27
75°
54°
28
75°
51°
29
74°
48°
30
67°
49°
1
68°
50°
2
73°
51°
3
Hist. Avg.
68°
50°
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 67° to 82°, with overnight lows between 45° and 62°. The average high for September is 74° with an average low of 54°. 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.
