S
M
T
W
T
F
S
30
67°
41°
31
70°
42°
1
72°
42°
2
71°
39°
3
65°
40°
4
63°
38°
5
63°
36°
6
64°
38°
7
69°
38°
8
70°
41°
9
69°
40°
10
69°
40°
11
68°
38°
12
69°
39°
13
67°
36°
14
62°
32°
15
63°
34°
16
62°
35°
17
63°
38°
18
67°
40°
19
67°
30°
20
60°
29°
21
Hist. Avg.
71°
37°
22
Hist. Avg.
70°
37°
23
Hist. Avg.
70°
36°
24
Hist. Avg.
70°
36°
25
Hist. Avg.
69°
36°
26
Hist. Avg.
69°
35°
27
Hist. Avg.
69°
35°
28
Hist. Avg.
68°
34°
29
Hist. Avg.
68°
34°
30
Hist. Avg.
67°
34°
1
Hist. Avg.
67°
33°
2
Hist. Avg.
67°
33°
3
Hist. Avg.
66°
33°
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 60° to 72°, with overnight lows between 29° and 42°. The average high for September is 66° with an average low of 38°. 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.
