S
M
T
W
T
F
S
26
73°
55°
27
70°
52°
28
70°
46°
29
82°
55°
30
73°
57°
1
66°
55°
2
59°
50°
3
72°
41°
4
81°
45°
5
82°
48°
6
84°
59°
7
79°
59°
8
72°
50°
9
77°
57°
10
86°
59°
11
86°
57°
12
70°
48°
13
81°
46°
14
81°
57°
15
79°
43°
16
88°
48°
17
91°
59°
18
91°
63°
19
93°
61°
20
93°
61°
21
95°
64°
22
93°
68°
23
86°
68°
24
82°
71°
25
83°
70°
26
83°
71°
27
85°
71°
28
89°
68°
29
86°
67°
30
78°
66°
31
76°
59°
1
78°
62°
2
81°
64°
3
84°
63°
4
85°
65°
5
86°
66°
6
83°
71°
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 76° to 89°, with overnight lows between 59° and 71°. The average high for May is 83° with an average low of 67°. 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.
