S
M
T
W
T
F
S
29
43°
25°
30
44°
28°
1
45°
33°
2
48°
37°
3
45°
38°
4
54°
39°
5
48°
39°
6
49°
38°
7
48°
36°
8
43°
34°
9
42°
32°
10
42°
31°
11
57°
37°
12
59°
26°
13
59°
24°
14
42°
23°
15
41°
24°
16
44°
23°
17
40°
29°
18
46°
37°
19
51°
39°
20
56°
38°
21
56°
36°
22
55°
38°
23
55°
39°
24
58°
30°
25
58°
23°
26
52°
22°
27
39°
29°
28
45°
35°
29
51°
36°
30
52°
38°
31
56°
40°
1
55°
33°
2
57°
25°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Monticello
Monticello's December 2026 forecast shows daily high temperatures ranging from 39° to 59°, with overnight lows between 22° and 40°. The average high for December is 50° with an average low of 32°. 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 Monticello. See also: January | February | March.
