Upwelling at the Coast
Our upwelling index thermometer provides you with a quick look at the ocean's potential to upwell cold water from the sea floor, warning you of the potential of a cold day of swimming.

Upwelling usually occurs during the summer months from May to September. Prolonged Southwest winds force the warm surface water away from the coast causing cold water from the bottom of the ocean to surface. Upwelling is the cause of frigid beach days which can occur even when the weather is hot.

How is the prediction calculated?
We base our index on scientific data obtained from Satellite Temperature maps, CODAR surface currents, and meteorological weather data.

What does it mean?
When only the red bar shows, beach temperatures should be near normal. A mix of red and blue signify the right conditions for upwelling to occur, provided the wind blows in the right direction (literally). When the blue bar reaches the top it is highly likely that upwelling is occurring. The water on shore will be colder than normal for some beaches along the coast. To see which beaches have colder than normal temperatures, see our Sea Surface Temperature Images.

Our lesson on upwelling has more information about coastal upwelling and its effects on New Jersey beaches.