S
M
T
W
T
F
S
30
80°
52°
31
76°
66°
1
77°
66°
2
73°
65°
3
83°
70°
4
84°
63°
5
79°
59°
6
72°
52°
7
79°
47°
8
80°
52°
9
79°
55°
10
86°
66°
11
77°
53°
12
76°
48°
13
76°
63°
14
75°
51°
15
68°
48°
16
74°
47°
17
79°
60°
18
81°
58°
19
69°
56°
20
70°
63°
21
70°
57°
22
65°
55°
23
67°
57°
24
67°
55°
25
67°
53°
26
66°
54°
27
68°
53°
28
70°
54°
29
67°
53°
30
68°
54°
1
69°
54°
2
68°
51°
3
65°
55°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Mattituck
Mattituck's September 2026 forecast shows daily high temperatures ranging from 65° to 70°, with overnight lows between 51° and 63°. The average high for September is 68° with an average low of 55°. 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 Mattituck. See also: October | November | December.
