S
M
T
W
T
F
S
29
58°
31°
30
56°
27°
1
58°
29°
2
58°
27°
3
61°
26°
4
56°
26°
5
57°
32°
6
63°
42°
7
67°
36°
8
70°
28°
9
66°
27°
10
59°
28°
11
60°
35°
12
61°
36°
13
57°
31°
14
61°
26°
15
56°
26°
16
54°
27°
17
56°
29°
18
56°
37°
19
59°
38°
20
60°
41°
21
67°
41°
22
68°
40°
23
66°
37°
24
69°
34°
25
66°
36°
26
65°
36°
27
63°
28°
28
64°
31°
29
55°
25°
30
59°
21°
31
60°
20°
1
47°
23°
2
51°
22°
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 47° to 70°, with overnight lows between 20° and 42°. The average high for December is 60° with an average low of 31°. 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.
