S
M
T
W
T
F
S
30
85°
75°
31
83°
76°
1
82°
73°
2
82°
74°
3
84°
77°
4
86°
73°
5
82°
72°
6
82°
72°
7
83°
74°
8
82°
73°
9
82°
75°
10
83°
74°
11
84°
75°
12
84°
74°
13
85°
76°
14
83°
76°
15
80°
75°
16
81°
74°
17
79°
73°
18
79°
74°
19
80°
71°
20
82°
69°
21
82°
71°
22
79°
69°
23
77°
72°
24
78°
74°
25
78°
74°
26
79°
73°
27
81°
74°
28
84°
71°
29
84°
71°
30
83°
72°
1
85°
68°
2
83°
65°
3
79°
64°
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 77° to 86°, with overnight lows between 64° and 77°. The average high for September is 82° with an average low of 73°. 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.
