S
M
T
W
T
F
S
26
83°
64°
27
84°
64°
28
80°
59°
29
83°
57°
30
87°
57°
31
87°
65°
1
76°
68°
2
77°
61°
3
77°
59°
4
80°
65°
5
81°
63°
6
85°
64°
7
82°
65°
8
85°
64°
9
82°
62°
10
80°
61°
11
80°
61°
12
79°
60°
13
80°
61°
14
82°
60°
15
77°
56°
16
77°
57°
17
86°
65°
18
86°
65°
19
87°
64°
20
85°
63°
21
84°
63°
22
85°
62°
23
86°
64°
24
86°
64°
25
85°
63°
26
82°
63°
27
81°
62°
28
80°
61°
29
81°
62°
30
80°
61°
31
82°
61°
1
84°
60°
2
80°
56°
3
77°
56°
4
79°
58°
5
83°
57°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
August Weather in Port Jefferson
Port Jefferson's August 2026 forecast shows daily high temperatures ranging from 76° to 87°, with overnight lows between 56° and 68°. The average high for August is 82° with an average low of 62°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how August weather will actually feel in Port Jefferson. See also: September | October | November.
