S
M
T
W
T
F
S
30
92°
70°
31
93°
72°
1
98°
73°
2
98°
73°
3
97°
73°
4
96°
74°
5
99°
71°
6
90°
68°
7
90°
69°
8
86°
66°
9
85°
64°
10
85°
62°
11
81°
55°
12
83°
57°
13
82°
57°
14
78°
54°
15
83°
60°
16
83°
59°
17
82°
61°
18
83°
61°
19
83°
60°
20
82°
60°
21
82°
59°
22
81°
60°
23
82°
59°
24
81°
58°
25
81°
58°
26
80°
56°
27
81°
57°
28
80°
57°
29
79°
56°
30
80°
57°
1
79°
56°
2
79°
56°
3
78°
55°
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 78° to 99°, with overnight lows between 54° and 74°. The average high for September is 84° with an average low of 61°. 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.
