S
M
T
W
T
F
S
29
60°
44°
30
82°
61°
31
83°
64°
1
71°
51°
2
76°
57°
3
82°
65°
4
75°
46°
5
61°
40°
6
65°
38°
7
57°
44°
8
76°
41°
9
79°
54°
10
73°
56°
11
73°
49°
12
79°
59°
13
84°
67°
14
88°
70°
15
77°
64°
16
82°
60°
17
85°
60°
18
64°
42°
19
69°
38°
20
67°
40°
21
82°
48°
22
80°
53°
23
82°
56°
24
74°
59°
25
77°
55°
26
80°
53°
27
83°
62°
28
66°
54°
29
64°
41°
30
65°
48°
1
62°
41°
2
60°
40°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
April Weather in O'Fallon
O'Fallon's April 2026 forecast shows daily high temperatures ranging from 60° to 65°, with overnight lows between 40° and 48°. The average high for April is 63° with an average low of 43°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how April weather will actually feel in O'Fallon. See also: May | June | July.
