I lived (and played) in Florida as an adult for over 25 years. The only times that I was ever in the "ocean" and felt water that was warmer than my own body temperature was when I was in still waters that were very shallow. Some examples are 1) wading in knee-deep water in Ft. George Inlet at low tide casting for baitfish, and 2) snorkelling in the Gulf of Mexico just north of Marathon Key at low tide in 1-2 feet deep grass flats looking for lobsters. In the heat of the summer, this sort of thing is not uncommon.
So, I would say that if a person has an agenda to create a panic over global warming, it would not hard to manufacture misleading information that has a granule of truth to scare people into believing.