Click on a day for an hourly weather forecast
The temperatures in Princeton in September are comfortable with low of 17°C and and high up to 25°C.
You can expect about 3 to 8 days of rain in Princeton during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Princeton in September 2025.
If you’re planning to visit Princeton in the near future, we highly recommend that you review the 14 day weather forecast for Princeton before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 3° / -3° | 6 | 18 | 7 | 89 mm | Awful | Princeton in January |
| February | 5° / -2° | 7 | 14 | 7 | 117 mm | Awful | Princeton in February |
| March | 9° / 2° | 7 | 18 | 5 | 127 mm | Awful | Princeton in March |
| April | 15° / 7° | 6 | 24 | 1 | 105 mm | Good | Princeton in April |
| May | 21° / 12° | 7 | 24 | 0 | 130 mm | Ok | Princeton in May |
| June | 26° / 17° | 7 | 23 | 0 | 131 mm | Good | Princeton in June |
| July | 29° / 21° | 9 | 22 | 0 | 180 mm | Ok | Princeton in July |
| August | 28° / 20° | 7 | 24 | 0 | 174 mm | Good | Princeton in August |
| September | 25° / 17° | 5 | 25 | 0 | 111 mm | Perfect | Princeton in September |
| October | 18° / 11° | 5 | 25 | 0 | 134 mm | Good | Princeton in October |
| November | 11° / 5° | 5 | 24 | 1 | 91 mm | Ok | Princeton in November |
| December | 7° / 1° | 7 | 20 | 5 | 142 mm | Awful | Princeton in December |