S
M
T
W
T
F
S
30
78°
61°
31
80°
63°
1
80°
63°
2
79°
62°
3
80°
55°
4
73°
53°
5
72°
55°
6
73°
61°
7
79°
61°
8
79°
60°
9
73°
59°
10
72°
60°
11
77°
59°
12
75°
60°
13
77°
60°
14
77°
59°
15
76°
59°
16
77°
58°
17
72°
57°
18
76°
51°
19
68°
50°
20
69°
49°
21
65°
47°
22
66°
52°
23
69°
50°
24
66°
47°
25
65°
47°
26
65°
48°
27
70°
52°
28
71°
53°
29
70°
52°
30
71°
53°
1
63°
52°
2
67°
45°
3
64°
51°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Lemont
Lemont's September 2026 forecast shows daily high temperatures ranging from 63° to 80°, with overnight lows between 45° and 63°. The average high for September is 72° 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 Lemont. See also: October | November | December.
