S
M
T
W
T
F
S
26
54°
43°
27
60°
43°
28
62°
45°
29
62°
53°
30
64°
51°
1
65°
50°
2
63°
47°
3
63°
45°
4
65°
49°
5
66°
51°
6
65°
51°
7
64°
49°
8
65°
48°
9
66°
46°
10
65°
46°
11
65°
47°
12
64°
49°
13
65°
48°
14
64°
49°
15
65°
47°
16
64°
47°
17
66°
48°
18
66°
49°
19
67°
48°
20
66°
50°
21
67°
49°
22
68°
51°
23
69°
57°
24
73°
57°
25
71°
54°
26
68°
51°
27
69°
53°
28
71°
56°
29
69°
58°
30
68°
58°
31
69°
57°
1
70°
60°
2
73°
60°
3
70°
59°
4
74°
59°
5
78°
54°
6
75°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Port Jefferson
Port Jefferson's May 2026 forecast shows daily high temperatures ranging from 54° to 78°, with overnight lows between 43° and 60°. The average high for May is 67° with an average low of 51°. 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 Port Jefferson. See also: June | July | August.
