S
M
T
W
T
F
S
30
89°
61°
31
83°
65°
1
81°
66°
2
81°
58°
3
84°
58°
4
86°
65°
5
88°
64°
6
88°
57°
7
79°
56°
8
79°
56°
9
80°
58°
10
85°
59°
11
84°
60°
12
80°
61°
13
77°
57°
14
78°
62°
15
83°
61°
16
84°
54°
17
78°
53°
18
75°
53°
19
74°
54°
20
75°
57°
21
73°
54°
22
73°
52°
23
74°
57°
24
73°
58°
25
77°
58°
26
78°
57°
27
79°
52°
28
78°
56°
29
76°
57°
30
73°
57°
1
72°
55°
2
71°
50°
3
70°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Charleston
Charleston's September 2026 forecast shows daily high temperatures ranging from 70° to 89°, with overnight lows between 47° and 66°. The average high for September is 79° with an average low of 57°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Charleston. See also: October | November | December.
