S
M
T
W
T
F
S
26
85°
71°
27
88°
74°
28
82°
69°
29
69°
59°
30
64°
58°
1
65°
55°
2
74°
50°
3
81°
54°
4
81°
59°
5
85°
61°
6
61°
55°
7
72°
52°
8
80°
58°
9
86°
65°
10
78°
64°
11
76°
60°
12
80°
54°
13
87°
58°
14
90°
65°
15
87°
69°
16
87°
71°
17
88°
74°
18
89°
79°
19
82°
65°
20
82°
64°
21
76°
67°
22
86°
69°
23
81°
64°
24
87°
66°
25
88°
66°
26
87°
69°
27
79°
67°
28
83°
67°
29
83°
68°
30
85°
67°
31
83°
66°
1
82°
67°
2
82°
64°
3
83°
66°
4
83°
67°
5
86°
69°
6
88°
68°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Charleston
Charleston's May 2026 forecast shows daily high temperatures ranging from 79° to 88°, with overnight lows between 64° and 69°. The average high for May is 84° 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 Charleston. See also: June | July | August.
