S
M
T
W
T
F
S
28
94°
73°
29
93°
74°
30
97°
74°
1
96°
76°
2
93°
75°
3
91°
72°
4
92°
73°
5
90°
72°
6
89°
69°
7
86°
68°
8
90°
70°
9
89°
71°
10
88°
71°
11
88°
68°
12
89°
67°
13
91°
64°
14
83°
64°
15
83°
65°
16
84°
64°
17
88°
68°
18
90°
71°
19
91°
71°
20
90°
70°
21
89°
71°
22
87°
72°
23
91°
72°
24
92°
71°
25
91°
70°
26
90°
71°
27
91°
71°
28
92°
72°
29
92°
72°
30
91°
71°
31
91°
71°
1
90°
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 83° to 97°, with overnight lows between 64° and 76°. The average high for July is 90° with an average low of 70°. 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.
