S
M
T
W
T
F
S
30
79°
67°
31
78°
69°
1
82°
67°
2
71°
65°
3
84°
67°
4
84°
71°
5
79°
68°
6
76°
64°
7
78°
61°
8
80°
62°
9
82°
68°
10
84°
69°
11
79°
67°
12
78°
63°
13
79°
68°
14
75°
63°
15
72°
57°
16
77°
58°
17
82°
70°
18
80°
69°
19
69°
63°
20
69°
62°
21
72°
61°
22
65°
55°
23
66°
55°
24
66°
54°
25
72°
57°
26
68°
56°
27
69°
58°
28
66°
58°
29
68°
57°
30
70°
58°
1
69°
57°
2
71°
56°
3
67°
60°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Roosevelt Island
Roosevelt Island's September 2026 forecast shows daily high temperatures ranging from 65° to 72°, with overnight lows between 54° and 60°. The average high for September is 68° with an average low of 57°. 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 Roosevelt Island. See also: October | November | December.
