S
M
T
W
T
F
S
30
88°
64°
31
85°
69°
1
88°
67°
2
89°
64°
3
84°
63°
4
85°
64°
5
84°
66°
6
88°
67°
7
88°
68°
8
87°
67°
9
87°
68°
10
86°
67°
11
87°
67°
12
87°
66°
13
86°
67°
14
87°
66°
15
84°
65°
16
81°
65°
17
84°
60°
18
80°
60°
19
83°
61°
20
84°
63°
21
85°
64°
22
80°
61°
23
83°
62°
24
82°
63°
25
82°
60°
26
83°
61°
27
82°
61°
28
82°
61°
29
Hist. Avg.
79°
58°
30
Hist. Avg.
78°
58°
1
Hist. Avg.
78°
57°
2
Hist. Avg.
78°
57°
3
Hist. Avg.
78°
57°
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 80° to 89°, with overnight lows between 60° and 69°. The average high for September is 85° with an average low of 64°. 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.
