S
M
T
W
T
F
S
26
79°
54°
27
81°
50°
28
73°
55°
29
73°
52°
30
66°
43°
1
70°
37°
2
61°
43°
3
64°
32°
4
77°
37°
5
75°
43°
6
70°
57°
7
64°
41°
8
70°
34°
9
73°
41°
10
81°
43°
11
70°
43°
12
75°
37°
13
77°
45°
14
59°
37°
15
75°
32°
16
84°
45°
17
88°
52°
18
90°
57°
19
86°
61°
20
88°
57°
21
75°
64°
22
77°
66°
23
73°
63°
24
82°
61°
25
79°
66°
26
82°
66°
27
78°
64°
28
80°
56°
29
80°
61°
30
77°
55°
31
79°
59°
1
76°
51°
2
76°
53°
3
74°
54°
4
74°
55°
5
74°
55°
6
76°
57°
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 74° to 80°, with overnight lows between 51° and 64°. The average high for May is 77° 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.
