Oh, no--no way I'm tough enough to swim Lake Michigan in May! It's too cold for me (sans wetsuit) even in midsummer.
I recently took a teaching job in the Marshall Islands, and am now living just 8 degrees north of the equator, way out in the middle of the Pacific, during the school year. Ocean temps here are about 80 F year-round, with amazing visibility. For a swimmer/sailor, it's a perfect place to live. I've been swimming about 1-2 hours every day, sometimes around the lagoon, sometimes down to the next island and back--was out this evening and swam with a sea turtle. I've seen plenty of sharks, too (non-aggressive ones, they're pretty shy, actually). Pretty cool. And the salt water makes everything easier, with more buoyancy and thicker water to press against.
I do NOT miss the pool...