S
M
T
W
T
F
S
26
77°
61°
27
76°
51°
28
70°
49°
29
66°
43°
30
66°
42°
1
59°
40°
2
60°
41°
3
65°
48°
4
66°
48°
5
68°
53°
6
67°
51°
7
70°
52°
8
82°
61°
9
66°
49°
10
67°
48°
11
68°
56°
12
71°
51°
13
68°
49°
14
68°
50°
15
69°
49°
16
69°
51°
17
72°
54°
18
78°
60°
19
78°
61°
20
79°
62°
21
80°
61°
22
79°
62°
23
80°
62°
24
81°
63°
25
81°
62°
26
77°
57°
27
76°
56°
28
76°
59°
29
80°
61°
30
82°
63°
31
83°
64°
1
84°
65°
2
84°
65°
3
85°
66°
4
85°
66°
5
83°
65°
6
84°
67°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Bethalto
Bethalto's May 2026 forecast shows daily high temperatures ranging from 59° to 85°, with overnight lows between 40° and 67°. The average high for May is 74° with an average low of 56°. 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 Bethalto. See also: June | July | August.
