S
M
T
W
T
F
S
30
79°
55°
31
81°
56°
1
82°
56°
2
82°
55°
3
81°
48°
4
79°
46°
5
73°
49°
6
73°
54°
7
78°
54°
8
80°
53°
9
79°
54°
10
78°
52°
11
77°
50°
12
78°
52°
13
78°
53°
14
77°
53°
15
78°
52°
16
78°
45°
17
76°
52°
18
75°
50°
19
75°
47°
20
72°
42°
21
67°
40°
22
66°
47°
23
67°
44°
24
71°
41°
25
65°
39°
26
64°
39°
27
66°
45°
28
71°
46°
29
70°
42°
30
67°
41°
1
63°
44°
2
63°
37°
3
Hist. Avg.
64°
41°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Charlestown
Charlestown's September 2026 forecast shows daily high temperatures ranging from 63° to 82°, with overnight lows between 37° and 56°. The average high for September is 74° with an average low of 48°. 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 Charlestown. See also: October | November | December.
