S
M
T
W
T
F
S
30
93°
65°
31
95°
73°
1
97°
74°
2
97°
73°
3
99°
74°
4
100°
74°
5
100°
73°
6
90°
70°
7
87°
69°
8
93°
74°
9
95°
75°
10
85°
67°
11
86°
67°
12
89°
67°
13
94°
68°
14
90°
67°
15
88°
64°
16
85°
63°
17
88°
64°
18
88°
63°
19
86°
60°
20
82°
57°
21
87°
62°
22
83°
62°
23
84°
61°
24
86°
63°
25
86°
63°
26
85°
62°
27
86°
62°
28
84°
61°
29
85°
62°
30
85°
62°
1
83°
58°
2
82°
52°
3
71°
48°
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 71° to 95°, with overnight lows between 48° and 75°. The average high for September is 86° with an average low of 63°. 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.
