Just got back from Tampa Bay for two weeks. I'm from Michigan, and I wouldn't have been going to the waterpark. The temps were in the 60's unless your going to Miami.
The Gulf of Mexico was 65, and I walked into it up to my knees. I have also been in Lake Superior which never gets to 65, so maybe I'm a nut. Maybe you get lucky... but the temps in Florida this year are way below average.
Yes..We have been below average so it would be very chilly! Go to the theme parks instead and enjoy your time here! Be sure to visit Wonderworks on International drive...Intresting and fun place! Park in the garage in the back of it....