S
M
T
W
T
F
S
29
40°
34°
30
43°
39°
1
45°
38°
2
46°
34°
3
40°
34°
4
40°
32°
5
39°
32°
6
39°
32°
7
40°
35°
8
44°
35°
9
42°
36°
10
45°
38°
11
46°
40°
12
45°
38°
13
46°
37°
14
43°
37°
15
44°
33°
16
41°
32°
17
39°
32°
18
39°
33°
19
40°
31°
20
39°
34°
21
40°
39°
22
46°
38°
23
46°
38°
24
45°
37°
25
45°
36°
26
44°
37°
27
43°
35°
28
44°
36°
29
43°
37°
30
43°
39°
31
44°
38°
1
46°
36°
2
44°
34°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Castleton
Castleton's December 2026 forecast shows daily high temperatures ranging from 39° to 46°, with overnight lows between 31° and 40°. The average high for December is 43° with an average low of 36°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how December weather will actually feel in Castleton. See also: January | February | March.
