S
M
T
W
T
F
S
30
73°
51°
31
73°
50°
1
72°
52°
2
72°
53°
3
73°
52°
4
70°
52°
5
73°
53°
6
72°
52°
7
71°
51°
8
70°
49°
9
70°
52°
10
71°
50°
11
69°
49°
12
69°
48°
13
71°
49°
14
72°
55°
15
73°
55°
16
75°
54°
17
75°
51°
18
73°
48°
19
74°
54°
20
75°
49°
21
69°
46°
22
70°
50°
23
69°
51°
24
67°
52°
25
66°
49°
26
70°
44°
27
71°
44°
28
62°
45°
29
61°
45°
30
60°
42°
1
Hist. Avg.
63°
45°
2
Hist. Avg.
63°
45°
3
Hist. Avg.
62°
44°
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 60° to 75°, with overnight lows between 42° and 55°. The average high for September is 70° with an average low of 50°. 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.
