S
M
T
W
T
F
S
26
75°
59°
27
80°
51°
28
68°
49°
29
66°
43°
30
66°
42°
1
64°
42°
2
65°
45°
3
67°
48°
4
69°
54°
5
70°
53°
6
71°
55°
7
65°
43°
8
67°
47°
9
67°
47°
10
68°
49°
11
72°
59°
12
72°
56°
13
70°
51°
14
68°
50°
15
68°
50°
16
69°
51°
17
69°
53°
18
70°
55°
19
69°
52°
20
69°
51°
21
70°
52°
22
72°
54°
23
74°
57°
24
74°
54°
25
71°
54°
26
72°
55°
27
72°
57°
28
73°
56°
29
73°
60°
30
74°
57°
31
74°
58°
1
75°
58°
2
77°
59°
3
78°
60°
4
81°
64°
5
84°
66°
6
86°
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 64° to 86°, with overnight lows between 42° and 67°. The average high for May is 72° with an average low of 53°. 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.
