S
M
T
W
T
F
S
30
80°
52°
31
76°
66°
1
73°
65°
2
74°
66°
3
78°
69°
4
81°
64°
5
78°
60°
6
75°
63°
7
78°
65°
8
76°
61°
9
75°
62°
10
76°
62°
11
75°
65°
12
77°
64°
13
77°
61°
14
75°
62°
15
71°
61°
16
72°
64°
17
75°
62°
18
70°
58°
19
70°
59°
20
71°
62°
21
74°
63°
22
77°
64°
23
77°
63°
24
76°
61°
25
75°
60°
26
75°
61°
27
76°
62°
28
75°
61°
29
76°
59°
30
68°
55°
1
66°
56°
2
67°
59°
3
73°
59°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Shelter Island
Shelter Island's September 2026 forecast shows daily high temperatures ranging from 66° to 81°, with overnight lows between 55° and 69°. The average high for September is 74° 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 September weather will actually feel in Shelter Island. See also: October | November | December.
