S
M
T
W
T
F
S
29
47°
34°
30
46°
38°
1
46°
37°
2
47°
38°
3
47°
37°
4
38°
31°
5
42°
34°
6
55°
31°
7
45°
27°
8
43°
24°
9
39°
25°
10
37°
23°
11
37°
23°
12
38°
24°
13
37°
26°
14
38°
31°
15
44°
30°
16
45°
31°
17
50°
25°
18
50°
25°
19
37°
22°
20
38°
20°
21
37°
21°
22
34°
21°
23
35°
24°
24
37°
29°
25
41°
33°
26
47°
36°
27
49°
32°
28
50°
31°
29
47°
29°
30
44°
30°
31
43°
29°
1
45°
25°
2
41°
26°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Sag Harbor
Sag Harbor's December 2026 forecast shows daily high temperatures ranging from 34° to 55°, with overnight lows between 20° and 38°. The average high for December is 43° with an average low of 29°. 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 Sag Harbor. See also: January | February | March.
