S
M
T
W
T
F
S
26
63°
39°
27
67°
48°
28
62°
49°
29
58°
38°
30
57°
35°
1
52°
34°
2
57°
29°
3
68°
44°
4
79°
49°
5
58°
39°
6
55°
38°
7
58°
38°
8
59°
40°
9
64°
47°
10
64°
45°
11
65°
46°
12
65°
47°
13
68°
47°
14
67°
47°
15
72°
48°
16
71°
49°
17
72°
52°
18
66°
51°
19
72°
55°
20
71°
54°
21
69°
45°
22
66°
45°
23
65°
47°
24
67°
46°
25
67°
47°
26
68°
48°
27
67°
48°
28
68°
49°
29
69°
53°
30
70°
58°
31
75°
54°
1
71°
54°
2
74°
59°
3
77°
59°
4
79°
58°
5
79°
61°
6
80°
61°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in St. Charles
St. Charles's May 2026 forecast shows daily high temperatures ranging from 55° to 80°, with overnight lows between 38° and 61°. The average high for May is 69° with an average low of 49°. 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 St. Charles. See also: June | July | August.
