S
M
T
W
T
F
S
29
57°
36°
30
55°
37°
1
56°
28°
2
41°
25°
3
44°
29°
4
52°
31°
5
51°
33°
6
40°
25°
7
39°
20°
8
38°
19°
9
38°
22°
10
41°
26°
11
45°
25°
12
48°
26°
13
45°
25°
14
40°
21°
15
42°
23°
16
40°
27°
17
41°
24°
18
40°
18°
19
39°
17°
20
37°
16°
21
35°
18°
22
36°
24°
23
42°
22°
24
38°
21°
25
37°
16°
26
37°
16°
27
38°
17°
28
37°
16°
29
36°
20°
30
36°
18°
31
37°
15°
1
37°
11°
2
35°
12°
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 35° to 57°, with overnight lows between 11° and 37°. The average high for December is 41° 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.
