S
M
T
W
T
F
S
30
85°
61°
31
88°
62°
1
90°
63°
2
88°
61°
3
84°
66°
4
89°
65°
5
89°
66°
6
88°
64°
7
86°
59°
8
83°
65°
9
88°
64°
10
87°
64°
11
83°
65°
12
88°
63°
13
87°
57°
14
81°
56°
15
80°
56°
16
80°
57°
17
81°
60°
18
85°
62°
19
86°
60°
20
85°
61°
21
80°
60°
22
84°
61°
23
84°
57°
24
85°
53°
25
78°
52°
26
79°
55°
27
83°
57°
28
84°
58°
29
Hist. Avg.
78°
53°
30
Hist. Avg.
78°
52°
1
Hist. Avg.
77°
52°
2
Hist. Avg.
77°
52°
3
Hist. Avg.
77°
51°
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 78° to 90°, with overnight lows between 52° and 66°. The average high for September is 85° 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.
