Hilary,
You'll want a shorty for kiting that time of the year. Don't think you'll be getting in super warm waters..
spots and info on them:
http://www.kiteboardingflorida.com/Kite ... orida.html
I used to kite in ft. lauderdale and Boca Raton a lot.. as i am from there. In short, every beach is kiteable ie. every inch of coastline. Ask the lifeguard from where you can launch, towers everywhere... except the keys...
Kiting the keys is meh to be honest. Unless you can get in on the west side of the keys for glassy flat water (offshore, you'll need boat support) or charter a boat to some sand flats (already talking 4hr drive south of miami to Key West) then its all meh, at most.
Unbeknownst to tourists, there are NO beaches in the keys. What say you. You heard right. There are little chunks of quasi-accessible sand, some couple of feet wide (on low tide haha) where you can pump up. You'll need to drift launch or have someone help you get the kite in the wind and not on the rocks.
If it was me, i'd kite Miami or Ft. laudy areas. Crandon park is fun and there's a way to kite it without paying the parking fee. Its nice there inside the Key Biscayne (not formally a "key"). Fun thing about FL is that short of it being a East wind, you can kite it. From the north or south means downwinders. West is usually a straight on beach wind. Choppy oceans, gusty and intermittent storm winds etc etc. Not even close to kiting in the bay : )
When i got visit family there now kiting is rarely part of my plan.... but somehow still always do 3/4 of the days i'm there
Have fun.