S
M
T
W
T
F
S
30
78°
60°
31
79°
61°
1
83°
56°
2
78°
55°
3
78°
56°
4
77°
54°
5
77°
54°
6
78°
57°
7
80°
55°
8
79°
59°
9
82°
59°
10
77°
58°
11
79°
58°
12
81°
57°
13
81°
58°
14
80°
58°
15
81°
57°
16
80°
55°
17
79°
56°
18
73°
57°
19
78°
56°
20
79°
56°
21
78°
54°
22
78°
48°
23
75°
54°
24
73°
54°
25
Hist. Avg.
74°
54°
26
Hist. Avg.
73°
54°
27
Hist. Avg.
73°
54°
28
Hist. Avg.
72°
53°
29
Hist. Avg.
72°
53°
30
Hist. Avg.
72°
52°
1
Hist. Avg.
71°
52°
2
Hist. Avg.
71°
52°
3
Hist. Avg.
70°
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 73° to 83°, with overnight lows between 48° and 61°. The average high for September is 79° 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.
