S
M
T
W
T
F
S
28
94°
73°
29
93°
77°
30
95°
77°
1
93°
76°
2
96°
74°
3
94°
74°
4
94°
69°
5
85°
69°
6
86°
68°
7
87°
70°
8
90°
69°
9
83°
71°
10
87°
71°
11
83°
71°
12
87°
68°
13
87°
64°
14
90°
69°
15
92°
73°
16
88°
74°
17
88°
72°
18
92°
72°
19
89°
70°
20
90°
69°
21
87°
67°
22
85°
63°
23
82°
62°
24
86°
67°
25
85°
68°
26
88°
70°
27
87°
67°
28
90°
70°
29
84°
68°
30
84°
70°
31
85°
68°
1
87°
72°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
July Weather in O'Fallon
O'Fallon's July 2026 forecast shows daily high temperatures ranging from 82° to 92°, with overnight lows between 62° and 74°. The average high for July is 87° with an average low of 69°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how July weather will actually feel in O'Fallon. See also: August | September | October.
