S
M
T
W
T
F
S
30
81°
67°
31
91°
70°
1
95°
72°
2
95°
73°
3
91°
71°
4
91°
71°
5
89°
69°
6
84°
64°
7
79°
64°
8
78°
61°
9
77°
62°
10
78°
63°
11
75°
57°
12
77°
56°
13
76°
58°
14
77°
56°
15
80°
61°
16
80°
61°
17
79°
60°
18
79°
61°
19
80°
61°
20
80°
60°
21
79°
61°
22
80°
60°
23
79°
60°
24
79°
59°
25
78°
60°
26
78°
59°
27
79°
58°
28
78°
58°
29
77°
57°
30
76°
57°
1
76°
56°
2
75°
56°
3
76°
55°
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 75° to 95°, with overnight lows between 55° and 73°. The average high for September is 80° with an average low of 61°. 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.
