S
M
T
W
T
F
S
30
90°
67°
31
94°
70°
1
98°
73°
2
97°
73°
3
98°
73°
4
97°
73°
5
92°
68°
6
88°
64°
7
88°
67°
8
90°
69°
9
95°
71°
10
90°
63°
11
83°
64°
12
85°
61°
13
83°
63°
14
82°
59°
15
83°
57°
16
82°
63°
17
83°
62°
18
79°
62°
19
75°
62°
20
79°
61°
21
81°
62°
22
83°
60°
23
80°
57°
24
78°
59°
25
80°
60°
26
79°
54°
27
71°
50°
28
71°
48°
29
69°
48°
30
71°
50°
1
70°
49°
2
72°
56°
3
70°
55°
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 69° to 98°, with overnight lows between 48° and 73°. The average high for September is 82° 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.
