S
M
T
W
T
F
S
30
77°
57°
31
78°
64°
1
84°
67°
2
68°
65°
3
87°
66°
4
84°
68°
5
80°
61°
6
78°
57°
7
79°
52°
8
81°
52°
9
80°
57°
10
86°
67°
11
80°
55°
12
79°
51°
13
80°
65°
14
73°
49°
15
73°
47°
16
79°
54°
17
72°
65°
18
79°
57°
19
69°
56°
20
66°
59°
21
70°
52°
22
63°
46°
23
63°
47°
24
65°
47°
25
68°
51°
26
65°
50°
27
62°
52°
28
66°
45°
29
65°
46°
30
68°
49°
1
67°
47°
2
68°
45°
3
62°
49°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Hackettstown
Hackettstown's September 2026 forecast shows daily high temperatures ranging from 62° to 70°, with overnight lows between 45° and 52°. The average high for September is 66° with an average low of 48°. 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 Hackettstown. See also: October | November | December.
