S
M
T
W
T
F
S
30
75°
58°
31
74°
58°
1
75°
62°
2
75°
67°
3
76°
67°
4
82°
66°
5
82°
66°
6
80°
59°
7
77°
58°
8
75°
58°
9
74°
57°
10
72°
57°
11
73°
58°
12
71°
57°
13
76°
61°
14
77°
63°
15
76°
62°
16
71°
59°
17
72°
60°
18
73°
61°
19
75°
54°
20
72°
56°
21
72°
54°
22
75°
52°
23
69°
52°
24
69°
53°
25
68°
57°
26
68°
51°
27
69°
57°
28
68°
56°
29
66°
49°
30
67°
50°
1
66°
56°
2
72°
52°
3
70°
50°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Islip Terrace
Islip Terrace's September 2026 forecast shows daily high temperatures ranging from 66° to 82°, with overnight lows between 49° and 67°. The average high for September is 73° with an average low of 58°. 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 Islip Terrace. See also: October | November | December.
