S
M
T
W
T
F
S
30
91°
80°
31
92°
78°
1
91°
78°
2
91°
76°
3
91°
79°
4
89°
77°
5
91°
75°
6
91°
75°
7
90°
77°
8
91°
78°
9
91°
80°
10
92°
79°
11
92°
78°
12
90°
80°
13
90°
78°
14
92°
77°
15
90°
79°
16
90°
77°
17
89°
78°
18
90°
77°
19
88°
78°
20
88°
74°
21
89°
75°
22
87°
73°
23
85°
72°
24
85°
75°
25
86°
75°
26
85°
74°
27
85°
75°
28
86°
75°
29
86°
74°
30
84°
73°
1
85°
74°
2
86°
75°
3
85°
74°
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 84° to 92°, with overnight lows between 72° and 80°. The average high for September is 88° with an average low of 76°. 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.
