S
M
T
W
T
F
S
30
77°
62°
31
78°
62°
1
76°
63°
2
76°
63°
3
75°
64°
4
74°
63°
5
75°
62°
6
76°
63°
7
74°
61°
8
75°
60°
9
73°
61°
10
74°
65°
11
73°
60°
12
73°
60°
13
76°
58°
14
76°
65°
15
75°
65°
16
74°
61°
17
71°
58°
18
71°
57°
19
72°
59°
20
76°
63°
21
72°
60°
22
70°
60°
23
75°
62°
24
73°
60°
25
75°
61°
26
68°
53°
27
71°
54°
28
66°
53°
29
65°
52°
30
65°
53°
1
Hist. Avg.
70°
53°
2
Hist. Avg.
69°
53°
3
Hist. Avg.
69°
52°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Setauket
Setauket's September 2026 forecast shows daily high temperatures ranging from 65° to 78°, with overnight lows between 52° and 65°. The average high for September is 73° with an average low of 60°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Setauket. See also: October | November | December.
