S
M
T
W
T
F
S
30
83°
63°
31
78°
64°
1
80°
64°
2
84°
59°
3
83°
54°
4
76°
55°
5
75°
63°
6
81°
58°
7
80°
54°
8
74°
57°
9
73°
58°
10
74°
61°
11
77°
60°
12
82°
61°
13
81°
60°
14
81°
55°
15
80°
53°
16
72°
55°
17
72°
50°
18
73°
50°
19
71°
47°
20
69°
47°
21
68°
49°
22
69°
56°
23
70°
48°
24
72°
54°
25
75°
56°
26
71°
55°
27
76°
56°
28
76°
52°
29
75°
50°
30
68°
50°
1
69°
51°
2
74°
52°
3
72°
53°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Chicago Heights
Chicago Heights's September 2026 forecast shows daily high temperatures ranging from 68° to 84°, with overnight lows between 47° and 64°. The average high for September is 75° with an average low of 55°. 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 Chicago Heights. See also: October | November | December.
