Main Beach, NY
Credit: Andrew Harrer / Bloomberg / Getty Images

The water at this East Hampton beach reaches a high of around 75 degrees in the summer. "Some people say that's too nippy," says Leatherman. "To me it's still warm enough, particularly on a hot day." The Main Beach is a safe place thanks to its "great team of lifeguards" and two- to three-foot-tall waves.

It also helps that locals take care of the place. "I've seen famous people picking up litter on that beach," he says. "People there really have a high respect for their beach."