S
M
T
W
T
F
S
30
63°
52°
31
64°
53°
1
63°
54°
2
67°
56°
3
67°
55°
4
65°
53°
5
63°
51°
6
61°
50°
7
61°
48°
8
63°
54°
9
66°
54°
10
64°
53°
11
65°
54°
12
63°
55°
13
64°
54°
14
64°
53°
15
63°
54°
16
65°
54°
17
63°
53°
18
62°
54°
19
64°
55°
20
65°
54°
21
59°
51°
22
62°
53°
23
63°
53°
24
64°
52°
25
63°
49°
26
62°
47°
27
60°
46°
28
61°
48°
29
61°
51°
30
60°
50°
1
61°
51°
2
61°
51°
3
62°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Castleton
Castleton's September 2026 forecast shows daily high temperatures ranging from 59° to 67°, with overnight lows between 46° and 56°. The average high for September is 63° 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.
