S
M
T
W
T
F
S
27
75°
60°
28
80°
52°
29
83°
49°
30
91°
64°
1
86°
61°
2
68°
47°
3
70°
48°
4
75°
47°
5
69°
44°
6
73°
48°
7
77°
51°
8
77°
53°
9
76°
49°
10
73°
51°
11
74°
49°
12
72°
48°
13
70°
47°
14
69°
46°
15
62°
45°
16
72°
51°
17
73°
51°
18
73°
50°
19
65°
45°
20
60°
41°
21
58°
38°
22
60°
46°
23
71°
50°
24
71°
49°
25
70°
48°
26
64°
42°
27
60°
42°
28
67°
46°
29
64°
41°
30
63°
46°
31
68°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
October Weather in O'Fallon
O'Fallon's October 2026 forecast shows daily high temperatures ranging from 58° to 86°, with overnight lows between 38° and 61°. The average high for October is 69° with an average low of 47°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how October weather will actually feel in O'Fallon. See also: November | December | January.
