S
M
T
W
T
F
S
26
81°
58°
27
83°
63°
28
80°
72°
29
79°
68°
30
77°
66°
31
83°
64°
1
83°
72°
2
82°
74°
3
79°
65°
4
83°
66°
5
81°
75°
6
87°
73°
7
89°
73°
8
85°
71°
9
88°
72°
10
87°
71°
11
86°
72°
12
88°
73°
13
83°
68°
14
83°
67°
15
82°
68°
16
81°
67°
17
81°
68°
18
80°
65°
19
78°
70°
20
80°
67°
21
79°
64°
22
78°
69°
23
84°
71°
24
85°
71°
25
84°
70°
26
80°
70°
27
77°
69°
28
77°
71°
29
81°
69°
30
82°
70°
31
81°
70°
1
82°
66°
2
75°
62°
3
74°
64°
4
74°
62°
5
75°
62°
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 74° to 89°, with overnight lows between 62° and 75°. The average high for August is 81° with an average low of 69°. 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.
