S
M
T
W
T
F
S
30
91°
65°
31
90°
65°
1
83°
64°
2
84°
62°
3
81°
58°
4
81°
58°
5
82°
64°
6
87°
62°
7
88°
63°
8
85°
62°
9
86°
63°
10
88°
58°
11
80°
55°
12
79°
55°
13
79°
56°
14
81°
61°
15
83°
61°
16
82°
60°
17
83°
60°
18
80°
53°
19
76°
50°
20
75°
52°
21
75°
52°
22
76°
57°
23
79°
57°
24
81°
59°
25
82°
52°
26
81°
49°
27
76°
51°
28
73°
48°
29
72°
47°
30
73°
54°
1
72°
56°
2
Hist. Avg.
74°
49°
3
Hist. Avg.
74°
49°
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 72° to 91°, with overnight lows between 47° and 65°. The average high for September is 81° with an average low of 57°. 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.
