S
M
T
W
T
F
S
29
55°
38°
30
58°
31°
1
55°
26°
2
42°
23°
3
46°
32°
4
54°
36°
5
49°
34°
6
42°
29°
7
42°
23°
8
40°
21°
9
40°
24°
10
43°
28°
11
46°
26°
12
51°
28°
13
47°
28°
14
44°
26°
15
46°
28°
16
44°
28°
17
42°
22°
18
41°
20°
19
40°
18°
20
37°
16°
21
36°
22°
22
41°
26°
23
41°
22°
24
40°
18°
25
38°
20°
26
39°
23°
27
40°
21°
28
40°
20°
29
39°
24°
30
39°
20°
31
40°
18°
1
37°
14°
2
36°
19°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Mount Vernon
Mount Vernon's December 2026 forecast shows daily high temperatures ranging from 36° to 58°, with overnight lows between 14° and 38°. The average high for December is 43° 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 Mount Vernon. See also: January | February | March.
