S
M
T
W
T
F
S
30
82°
61°
31
83°
64°
1
85°
63°
2
83°
57°
3
82°
55°
4
80°
56°
5
80°
56°
6
82°
56°
7
84°
58°
8
85°
63°
9
85°
60°
10
84°
55°
11
80°
60°
12
81°
59°
13
82°
53°
14
79°
53°
15
79°
51°
16
78°
53°
17
79°
58°
18
81°
52°
19
80°
59°
20
81°
57°
21
84°
57°
22
81°
59°
23
83°
59°
24
77°
58°
25
81°
58°
26
83°
57°
27
83°
57°
28
82°
56°
29
83°
56°
30
83°
57°
1
82°
56°
2
83°
48°
3
82°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in O'Fallon Township
O'Fallon Township's September 2026 forecast shows daily high temperatures ranging from 77° to 85°, with overnight lows between 46° and 64°. The average high for September is 82° with an average low of 57°. 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 O'Fallon Township. See also: October | November | December.
