S
M
T
W
T
F
S
30
85°
53°
31
85°
50°
1
84°
47°
2
75°
49°
3
73°
50°
4
79°
50°
5
83°
41°
6
73°
41°
7
71°
43°
8
73°
49°
9
79°
45°
10
75°
47°
11
77°
45°
12
80°
43°
13
72°
39°
14
69°
37°
15
68°
38°
16
69°
41°
17
70°
45°
18
78°
37°
19
69°
42°
20
69°
46°
21
78°
45°
22
78°
45°
23
77°
47°
24
77°
47°
25
78°
45°
26
77°
44°
27
75°
41°
28
67°
42°
29
65°
40°
30
67°
37°
1
62°
42°
2
65°
43°
3
Hist. Avg.
66°
35°
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 62° to 85°, with overnight lows between 37° and 53°. The average high for September is 74° with an average low of 44°. 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.
