S
M
T
W
T
F
S
29
45°
42°
30
47°
41°
1
47°
35°
2
44°
35°
3
43°
34°
4
43°
35°
5
42°
35°
6
43°
36°
7
43°
35°
8
44°
41°
9
44°
38°
10
45°
35°
11
43°
34°
12
42°
34°
13
41°
35°
14
45°
40°
15
48°
40°
16
44°
38°
17
46°
39°
18
45°
37°
19
42°
35°
20
42°
37°
21
46°
38°
22
47°
38°
23
47°
39°
24
46°
39°
25
48°
38°
26
47°
38°
27
46°
37°
28
47°
39°
29
47°
39°
30
46°
40°
31
48°
39°
1
48°
38°
2
47°
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 41° to 48°, with overnight lows between 34° and 42°. The average high for December is 45° with an average low of 37°. 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.
