S
M
T
W
T
F
S
30
80°
55°
31
79°
51°
1
78°
49°
2
71°
52°
3
71°
50°
4
72°
49°
5
71°
49°
6
70°
50°
7
73°
49°
8
76°
48°
9
74°
50°
10
73°
55°
11
71°
54°
12
75°
53°
13
74°
49°
14
75°
47°
15
70°
49°
16
71°
49°
17
66°
50°
18
67°
51°
19
72°
51°
20
Hist. Avg.
65°
42°
21
Hist. Avg.
65°
42°
22
Hist. Avg.
64°
42°
23
Hist. Avg.
64°
41°
24
Hist. Avg.
64°
41°
25
Hist. Avg.
63°
41°
26
Hist. Avg.
63°
41°
27
Hist. Avg.
63°
40°
28
Hist. Avg.
62°
40°
29
Hist. Avg.
62°
40°
30
Hist. Avg.
62°
39°
1
Hist. Avg.
61°
39°
2
Hist. Avg.
61°
39°
3
Hist. Avg.
60°
39°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
*Temporarily Unavailable
September Weather in Princeton
Princeton's September 2026 forecast shows daily high temperatures ranging from 66° to 80°, with overnight lows between 47° and 55°. The average high for September is 73° 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 Princeton. See also: October | November | December.
