S
M
T
W
T
F
S
29
45°
33°
30
47°
34°
1
46°
33°
2
45°
34°
3
48°
32°
4
46°
31°
5
46°
30°
6
45°
32°
7
46°
30°
8
44°
29°
9
37°
28°
10
40°
28°
11
41°
29°
12
40°
28°
13
41°
21°
14
42°
17°
15
36°
12°
16
30°
12°
17
29°
15°
18
28°
23°
19
34°
24°
20
39°
22°
21
37°
15°
22
33°
17°
23
35°
8°
24
32°
9°
25
27°
21°
26
34°
14°
27
34°
13°
28
27°
15°
29
29°
13°
30
27°
8°
31
28°
21°
1
36°
22°
2
39°
16°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Sullivan
Sullivan's December 2026 forecast shows daily high temperatures ranging from 27° to 48°, with overnight lows between 8° and 34°. The average high for December is 38° with an average low of 22°. 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 Sullivan. See also: January | February | March.
