S
M
T
W
T
F
S
26
63°
32°
27
61°
33°
28
61°
27°
29
48°
38°
30
52°
44°
1
51°
37°
2
57°
37°
3
45°
39°
4
58°
40°
5
56°
45°
6
60°
49°
7
58°
42°
8
55°
37°
9
57°
39°
10
57°
40°
11
58°
38°
12
59°
37°
13
60°
41°
14
54°
39°
15
56°
42°
16
54°
40°
17
55°
41°
18
56°
43°
19
54°
43°
20
59°
42°
21
62°
44°
22
60°
42°
23
56°
42°
24
55°
41°
25
57°
45°
26
59°
43°
27
57°
43°
28
58°
45°
29
57°
46°
30
58°
45°
31
58°
45°
1
59°
43°
2
58°
42°
3
59°
43°
4
58°
43°
5
58°
44°
6
59°
44°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Smithtown
Smithtown's May 2026 forecast shows daily high temperatures ranging from 45° to 62°, with overnight lows between 37° and 49°. The average high for May is 57° with an average low of 42°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Smithtown. See also: June | July | August.