S
M
T
W
T
F
S
26
68°
50°
27
68°
46°
28
57°
41°
29
54°
41°
30
50°
37°
1
52°
36°
2
63°
34°
3
72°
52°
4
70°
43°
5
52°
36°
6
46°
30°
7
59°
34°
8
72°
41°
9
63°
43°
10
63°
37°
11
66°
36°
12
77°
52°
13
68°
46°
14
75°
41°
15
86°
54°
16
81°
57°
17
64°
55°
18
73°
59°
19
68°
43°
20
59°
39°
21
61°
46°
22
65°
53°
23
74°
54°
24
77°
57°
25
83°
61°
26
82°
61°
27
78°
60°
28
77°
59°
29
78°
58°
30
77°
60°
31
76°
57°
1
77°
58°
2
76°
57°
3
74°
52°
4
76°
55°
5
69°
50°
6
69°
54°
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 61° to 83°, with overnight lows between 46° and 61°. The average high for May is 75° 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 St. Charles. See also: June | July | August.
