S
M
T
W
T
F
S
30
72°
55°
31
70°
52°
1
66°
52°
2
66°
59°
3
70°
57°
4
68°
55°
5
68°
50°
6
70°
48°
7
66°
55°
8
64°
52°
9
63°
48°
10
64°
43°
11
66°
48°
12
70°
46°
13
70°
54°
14
75°
54°
15
68°
54°
16
64°
52°
17
64°
52°
18
63°
50°
19
68°
55°
20
64°
50°
21
73°
45°
22
77°
55°
23
64°
45°
24
N/A
25
60°
49°
26
66°
50°
27
65°
48°
28
61°
51°
29
66°
60°
30
69°
54°
1
64°
52°
2
63°
51°
3
62°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Castleton
Castleton's September 2026 forecast shows daily high temperatures ranging from 60° to 69°, with overnight lows between 48° and 60°. The average high for September is 64° with an average low of 52°. 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 Castleton. See also: October | November | December.
