S
M
T
W
T
F
S
30
97°
64°
31
100°
70°
1
103°
71°
2
102°
72°
3
102°
73°
4
103°
73°
5
103°
75°
6
N/A
7
88°
64°
8
95°
71°
9
99°
72°
10
80°
60°
11
84°
63°
12
88°
65°
13
89°
64°
14
88°
63°
15
85°
59°
16
83°
60°
17
84°
60°
18
83°
59°
19
81°
55°
20
77°
60°
21
84°
60°
22
79°
60°
23
80°
59°
24
83°
61°
25
84°
61°
26
84°
60°
27
83°
60°
28
82°
59°
29
83°
60°
30
83°
60°
1
81°
56°
2
79°
50°
3
69°
46°
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 69° to 99°, with overnight lows between 46° and 72°. The average high for September is 84° with an average low of 60°. 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.
