S
M
T
W
T
F
S
30
79°
58°
31
80°
61°
1
83°
56°
2
80°
54°
3
78°
53°
4
77°
54°
5
79°
56°
6
83°
61°
7
86°
64°
8
87°
62°
9
83°
54°
10
78°
54°
11
79°
62°
12
80°
54°
13
85°
51°
14
76°
51°
15
77°
53°
16
76°
58°
17
82°
59°
18
81°
51°
19
76°
59°
20
81°
58°
21
83°
58°
22
83°
57°
23
82°
58°
24
81°
58°
25
82°
57°
26
80°
58°
27
82°
57°
28
82°
56°
29
81°
56°
30
82°
57°
1
82°
47°
2
81°
45°
3
79°
45°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Princeton
Princeton's September 2026 forecast shows daily high temperatures ranging from 76° to 87°, with overnight lows between 45° and 64°. The average high for September is 81° with an average low of 56°. 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 Princeton. See also: October | November | December.
