S
M
T
W
T
F
S
29
49°
39°
30
53°
42°
1
54°
41°
2
52°
41°
3
54°
39°
4
50°
38°
5
52°
36°
6
50°
39°
7
53°
37°
8
45°
34°
9
43°
32°
10
42°
30°
11
41°
35°
12
42°
33°
13
43°
31°
14
41°
28°
15
40°
28°
16
40°
29°
17
40°
30°
18
39°
34°
19
49°
33°
20
48°
25°
21
42°
26°
22
37°
26°
23
36°
28°
24
40°
28°
25
43°
26°
26
47°
21°
27
37°
21°
28
33°
22°
29
36°
21°
30
36°
28°
31
39°
30°
1
49°
23°
2
46°
19°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
December Weather in Smithtown
Smithtown's December 2026 forecast shows daily high temperatures ranging from 33° to 54°, with overnight lows between 19° and 42°. 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 Smithtown. See also: January | February | March.
