S
M
T
W
T
F
S
26
78°
51°
27
63°
59°
28
63°
54°
29
61°
44°
30
61°
40°
1
55°
45°
2
55°
42°
3
66°
43°
4
74°
54°
5
63°
45°
6
60°
44°
7
64°
39°
8
66°
48°
9
74°
50°
10
70°
53°
11
72°
46°
12
78°
46°
13
67°
44°
14
69°
52°
15
72°
63°
16
78°
63°
17
85°
65°
18
82°
66°
19
76°
57°
20
74°
56°
21
76°
55°
22
75°
54°
23
74°
54°
24
76°
56°
25
79°
60°
26
80°
57°
27
80°
63°
28
82°
62°
29
83°
62°
30
77°
58°
31
76°
56°
1
76°
57°
2
77°
55°
3
76°
57°
4
78°
62°
5
84°
65°
6
86°
66°
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 67° to 86°, with overnight lows between 44° and 66°. The average high for May is 78° 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 Charleston. See also: June | July | August.