S
M
T
W
T
F
S
29
43°
31°
30
42°
29°
1
41°
28°
2
41°
28°
3
42°
32°
4
43°
31°
5
45°
32°
6
43°
37°
7
41°
38°
8
42°
35°
9
42°
29°
10
40°
28°
11
51°
32°
12
49°
36°
13
44°
31°
14
50°
30°
15
42°
25°
16
39°
26°
17
38°
30°
18
40°
32°
19
44°
32°
20
45°
34°
21
48°
34°
22
49°
33°
23
49°
35°
24
48°
37°
25
51°
28°
26
51°
28°
27
49°
25°
28
38°
27°
29
37°
32°
30
46°
31°
31
46°
34°
1
48°
36°
2
49°
31°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Central Islip
Central Islip's December 2026 forecast shows daily high temperatures ranging from 37° to 51°, with overnight lows between 25° and 38°. The average high for December is 44° with an average low of 31°. 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 Central Islip. See also: January | February | March.
