S
M
T
W
T
F
S
30
90°
66°
31
91°
68°
1
97°
70°
2
97°
69°
3
97°
73°
4
93°
68°
5
86°
66°
6
85°
65°
7
84°
61°
8
82°
62°
9
85°
63°
10
83°
59°
11
84°
59°
12
82°
59°
13
84°
58°
14
81°
63°
15
80°
62°
16
75°
62°
17
75°
61°
18
78°
58°
19
81°
61°
20
82°
61°
21
81°
59°
22
82°
58°
23
82°
60°
24
81°
60°
25
81°
59°
26
80°
58°
27
79°
59°
28
77°
58°
29
80°
57°
30
79°
57°
1
78°
55°
2
78°
53°
3
77°
56°
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 75° to 97°, with overnight lows between 53° and 73°. The average high for September is 83° with an average low of 61°. 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.
