The temperature of the Atlantic Ocean at its surface level averages about 17 degrees Celsius, which is not quite warm enough for a comfortable swim. However, the ocean's temperature varies widely based on location, climate, depth and other factors.
Atlantic Ocean temperatures are warmest around the equator where the water absorbs the maximum amount of sun. Scientists have measured average temperatures for surface waters in the Persian Gulf at about 36 degrees Celsius. Conversely, average temperatures for the Atlantic Ocean in polar regions, which receive less sun, run as cold as minus-2 degrees Celsius, which is cold enough for the formation of surface ice.
In deeper waters, the Atlantic Ocean is universally cold. Water is denser near the bottom of the ocean and circulates less aggressively, leading to consistent temperatures of anywhere from 5 degrees Celsius to minus-3 degrees Celsius. Overall, water temperatures in the Atlantic vary based on the flow of the current, as warmer water replaces colder water.
In the United States, the Atlantic Ocean is warmest in the south Florida region, with an average of 22 degrees Celsius during the months of December, January and February. By contrast, the waters off the coast of Maine are barely above freezing, averaging about 2 to 5 degrees Celsius in those months.