S
M
T
W
T
F
S
29
43°
35°
30
46°
35°
1
48°
36°
2
49°
35°
3
49°
34°
4
36°
25°
5
45°
22°
6
39°
18°
7
31°
20°
8
34°
22°
9
35°
21°
10
35°
21°
11
36°
19°
12
34°
19°
13
35°
24°
14
37°
27°
15
35°
30°
16
41°
26°
17
43°
21°
18
37°
21°
19
35°
20°
20
34°
19°
21
38°
22°
22
36°
25°
23
41°
26°
24
40°
25°
25
38°
26°
26
36°
24°
27
35°
21°
28
34°
20°
29
33°
18°
30
34°
17°
31
32°
16°
1
33°
17°
2
34°
18°
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 31° to 49°, with overnight lows between 16° and 36°. The average high for December is 38° with an average low of 24°. 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.
