S
M
T
W
T
F
S
29
49°
38°
30
49°
30°
1
49°
33°
2
48°
24°
3
49°
21°
4
35°
20°
5
34°
21°
6
34°
20°
7
35°
23°
8
39°
25°
9
37°
26°
10
33°
23°
11
32°
19°
12
32°
22°
13
33°
19°
14
31°
17°
15
29°
12°
16
28°
13°
17
25°
24°
18
33°
28°
19
39°
28°
20
44°
25°
21
42°
29°
22
41°
31°
23
45°
29°
24
44°
25°
25
40°
23°
26
37°
26°
27
38°
28°
28
41°
30°
29
42°
29°
30
43°
27°
31
43°
24°
1
41°
21°
2
37°
20°
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 25° to 49°, with overnight lows between 12° and 38°. The average high for December is 39° 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 New Haven. See also: January | February | March.
