S
M
T
W
T
F
S
26
81°
51°
27
83°
61°
28
66°
55°
29
64°
50°
30
67°
40°
1
64°
44°
2
61°
44°
3
78°
41°
4
79°
58°
5
70°
46°
6
63°
43°
7
68°
39°
8
77°
47°
9
81°
56°
10
70°
49°
11
78°
44°
12
83°
51°
13
75°
51°
14
75°
45°
15
84°
58°
16
80°
68°
17
89°
63°
18
80°
65°
19
79°
62°
20
67°
55°
21
69°
53°
22
68°
61°
23
73°
64°
24
81°
59°
25
81°
54°
26
84°
61°
27
83°
66°
28
87°
63°
29
84°
66°
30
83°
63°
31
82°
65°
1
84°
63°
2
82°
58°
3
81°
58°
4
82°
64°
5
87°
68°
6
87°
64°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Caseyville
Caseyville's May 2026 forecast shows daily high temperatures ranging from 81° to 87°, with overnight lows between 58° and 68°. The average high for May is 84° with an average low of 63°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Caseyville. See also: June | July | August.
