S
M
T
W
T
F
S
26
76°
55°
27
73°
49°
28
59°
46°
29
60°
40°
30
60°
40°
1
60°
37°
2
63°
33°
3
75°
48°
4
83°
50°
5
60°
44°
6
59°
38°
7
71°
41°
8
74°
40°
9
77°
46°
10
71°
37°
11
78°
45°
12
80°
55°
13
76°
48°
14
80°
46°
15
86°
58°
16
87°
63°
17
79°
66°
18
78°
63°
19
65°
48°
20
63°
42°
21
67°
52°
22
69°
55°
23
74°
55°
24
82°
51°
25
85°
59°
26
86°
59°
27
83°
62°
28
82°
62°
29
79°
59°
30
71°
55°
31
78°
55°
1
79°
57°
2
76°
56°
3
82°
60°
4
81°
59°
5
80°
58°
6
77°
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 71° to 86°, with overnight lows between 55° and 62°. The average high for May is 80° with an average low of 59°. 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.
