S
M
T
W
T
F
S
30
81°
63°
31
82°
66°
1
83°
66°
2
85°
67°
3
87°
68°
4
87°
68°
5
81°
67°
6
81°
64°
7
77°
56°
8
81°
57°
9
84°
62°
10
82°
63°
11
77°
62°
12
77°
61°
13
82°
62°
14
78°
60°
15
77°
58°
16
74°
57°
17
78°
57°
18
75°
56°
19
73°
53°
20
72°
51°
21
78°
56°
22
76°
55°
23
75°
54°
24
74°
54°
25
76°
53°
26
76°
55°
27
75°
54°
28
75°
54°
29
76°
53°
30
75°
53°
1
74°
52°
2
73°
51°
3
72°
46°
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 84°, with overnight lows between 46° and 63°. The average high for September is 76° with an average low of 56°. 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.
