New Jersey (United States): where to swim in September?
New Jersey, in September: the sea is at 22.7 °C on average along the coast, from 21.9 °C to 23.2 °C depending on the spot. Where the water is warmest (23.2 °C), it is warm. Ideal for long swims and for being in the water all day.
Sea temperature, month by month
| Month | Average temperature | Depending on the spot | Where it is warmest |
|---|---|---|---|
| January | 7.5 °C | 4.5 °C – 9.8 °C | very cold |
| February | 6.1 °C | 3.7 °C – 8.5 °C | very cold |
| March | 6.5 °C | 5.5 °C – 7.9 °C | very cold |
| April | 9.1 °C | 8.3 °C – 9.8 °C | very cold |
| May | 13.4 °C | 12.4 °C – 14.9 °C | cold |
| June | 19.1 °C | 18.1 °C – 20.3 °C | pleasant |
| July | 24.0 °C | 23.3 °C – 24.6 °C | warm |
| August | 24.7 °C | 23.9 °C – 25.6 °C | warm |
| September | 22.7 °C | 21.9 °C – 23.2 °C | warm |
| October | 18.8 °C | 18.3 °C – 19.5 °C | pleasant |
| November | 14.3 °C | 12.7 °C – 15.1 °C | cool |
| December | 10.7 °C | 8.2 °C – 12.5 °C | cold |
Compared with August, the water cools down by 2.0 °C in September. The warmest month: August (24.7 °C). The coldest: February (6.1 °C).
Nearby, in September
- Maryland 23.9 °C · warm
- Massachusetts 19.0 °C · pleasant
- New York 21.5 °C · pleasant
And right now?
For the temperature measured right now, station by station and to the hour: New Jersey: water temperature
Frequently asked questions
What is the sea temperature in September?
New Jersey, in September: 22.7 °C on average along the coast, from 21.9 °C in the coolest waters to 23.2 °C in the warmest (average of the years 2011 to 2025).
Can you swim in September?
Where the water is warmest (23.2 °C), it is warm. Ideal for long swims and for being in the water all day.
What is the best month for swimming?
The water is warmest in August (24.7 °C on average) and coldest in February (6.1 °C). Where the water is warmest, it goes above 20 °C in these months: June, July, August, September.
What temperature do you need to swim comfortably?
Below 15 °C the water is cold: the cold takes your breath away and tires you quickly. Between 20 °C and 25 °C most people find it pleasant. Below 10 °C it is very cold.
Where do these temperatures come from?
These are averages of the sea surface temperature from 2011 to 2025, computed from NOAA satellite images (OISST, one value about every 50 km), in a 100 km strip along the coasts of the main country: distant territories (overseas, remote islands) are not counted. It is an estimate, not a measurement taken at the beach: lakes and rivers are not included.