S
M
T
W
T
F
S
30
82°
64°
31
82°
65°
1
83°
65°
2
82°
64°
3
81°
58°
4
80°
55°
5
79°
56°
6
80°
56°
7
83°
57°
8
85°
61°
9
86°
62°
10
82°
55°
11
79°
55°
12
79°
57°
13
80°
54°
14
78°
53°
15
76°
53°
16
77°
52°
17
76°
53°
18
78°
58°
19
80°
54°
20
77°
57°
21
81°
58°
22
81°
60°
23
83°
59°
24
78°
58°
25
77°
58°
26
76°
57°
27
78°
57°
28
82°
56°
29
82°
56°
30
81°
55°
1
80°
57°
2
81°
51°
3
81°
46°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in New Haven
New Haven's September 2026 forecast shows daily high temperatures ranging from 76° to 86°, with overnight lows between 46° and 65°. The average high for September is 80° 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 New Haven. See also: October | November | December.
