S
M
T
W
T
F
S
29
52°
39°
30
56°
36°
1
56°
36°
2
53°
27°
3
55°
24°
4
44°
23°
5
40°
22°
6
39°
21°
7
40°
22°
8
43°
26°
9
44°
28°
10
41°
24°
11
39°
21°
12
37°
24°
13
37°
20°
14
38°
19°
15
35°
16°
16
33°
14°
17
32°
23°
18
37°
30°
19
39°
32°
20
49°
26°
21
50°
32°
22
49°
33°
23
51°
34°
24
52°
30°
25
50°
29°
26
47°
30°
27
47°
30°
28
48°
32°
29
50°
34°
30
51°
31°
31
51°
28°
1
50°
24°
2
45°
23°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in New Haven
New Haven's December 2026 forecast shows daily high temperatures ranging from 32° to 56°, with overnight lows between 14° and 39°. The average high for December is 45° 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 New Haven. See also: January | February | March.
