United States: where to swim in April?
United States, in April: the sea is at 16.1 °C on average along the coast, from 7.5 °C to 24.2 °C depending on the spot. Where the water is warmest (24.2 °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 | 14.4 °C | 7.1 °C – 22.1 °C | pleasant |
| February | 13.8 °C | 5.4 °C – 21.7 °C | pleasant |
| March | 14.5 °C | 5.6 °C – 22.4 °C | pleasant |
| April | 16.1 °C | 7.5 °C – 24.2 °C | warm |
| May | 18.5 °C | 11.0 °C – 26.0 °C | warm |
| June | 21.2 °C | 12.5 °C – 28.8 °C | very warm |
| July | 23.2 °C | 13.8 °C – 29.9 °C | very warm |
| August | 23.8 °C | 14.7 °C – 30.4 °C | very warm |
| September | 23.0 °C | 14.5 °C – 29.4 °C | very warm |
| October | 21.2 °C | 13.5 °C – 28.2 °C | very warm |
| November | 18.2 °C | 11.5 °C – 25.6 °C | warm |
| December | 16.1 °C | 9.2 °C – 23.7 °C | warm |
Compared with March, the water warms up by 1.6 °C in April. The warmest month: August (23.8 °C). The coldest: February (13.8 °C).
Where the water is warmest in April
- Hawaii 24.9 °C · warm
- Florida 24.0 °C · warm
- Louisiana 22.4 °C · warm
- Texas 22.2 °C · warm
- Alabama 21.5 °C · pleasant
- South Carolina 20.3 °C · pleasant
- Georgia 20.1 °C · pleasant
- North Carolina 18.8 °C · warm
- California 12.8 °C · cool
- Virginia 11.5 °C · cold
- Maryland 11.2 °C · cold
- Oregon 10.4 °C · cold
- Washington 9.9 °C · cold
- New Jersey 9.1 °C · very cold
- New York 7.9 °C · very cold
- Massachusetts 6.9 °C · very cold
- Maine 5.5 °C · very cold
- Alaska 1.7 °C · very cold
And right now?
For the temperature measured right now, station by station and to the hour: United States: water temperature
Frequently asked questions
What is the sea temperature in April?
United States, in April: 16.1 °C on average along the coast, from 7.5 °C in the coolest waters to 24.2 °C in the warmest (average of the years 2011 to 2025).
Can you swim in April?
Where the water is warmest (24.2 °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 (23.8 °C on average) and coldest in February (13.8 °C). Where the water is warmest, it goes above 20 °C in these months: January, February, March, April, May, June, July, August, September, October, November, December.
Where is the water warmest in April?
The warmest in April: Hawaii (24.9 °C), Florida (24.0 °C), Louisiana (22.4 °C). The coolest: Alaska (1.7 °C).
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.