We went to Corolla on the Outer Banks in early June a few years ago and the ocean water was COLD. We stayed in the cement pond. Nice area though. We were wondering when in the hell the water actually gets warm....
My answer would be that the ocean never actually gets warm north of Nags Head. If you want warm ocean water on the NC Outer Banks, Hatteras Island is as far north as it goes, and fairly chilly even there north of Avon. No more Gulf Stream at that point. Labrador Current.