S
M
T
W
T
F
S
29
52°
40°
30
57°
39°
1
56°
40°
2
55°
34°
3
44°
32°
4
51°
31°
5
56°
38°
6
51°
35°
7
43°
28°
8
42°
24°
9
41°
24°
10
41°
27°
11
42°
30°
12
41°
27°
13
43°
25°
14
42°
24°
15
42°
30°
16
43°
33°
17
44°
32°
18
48°
29°
19
47°
24°
20
42°
23°
21
40°
22°
22
40°
24°
23
43°
27°
24
42°
24°
25
41°
23°
26
40°
20°
27
39°
22°
28
38°
21°
29
39°
23°
30
40°
26°
31
44°
22°
1
43°
19°
2
38°
17°
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 38° to 57°, with overnight lows between 17° and 40°. The average high for December is 44° with an average low of 27°. 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.
