S
M
T
W
T
F
S
30
90°
58°
31
82°
58°
1
76°
56°
2
77°
60°
3
73°
53°
4
77°
54°
5
80°
55°
6
82°
56°
7
86°
58°
8
91°
61°
9
94°
64°
10
95°
63°
11
96°
62°
12
92°
61°
13
89°
59°
14
90°
55°
15
92°
58°
16
87°
58°
17
91°
57°
18
91°
56°
19
84°
53°
20
86°
57°
21
89°
56°
22
90°
57°
23
85°
53°
24
81°
50°
25
80°
51°
26
80°
50°
27
79°
49°
28
80°
50°
29
81°
49°
30
80°
53°
1
79°
49°
2
80°
50°
3
84°
54°
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 73° to 96°, with overnight lows between 49° and 64°. The average high for September is 85° with an average low of 55°. 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.
