There is currently a thread on KF of which Rick is a part discussing cold weather and kiting.
It might seem silly to talk about hypothermia in Florida, but it's not silly at all. Most of us have only wetsuits, and many of them are just so-so.
I have noticed from personal experience and in watching others that when the air temperature is at or below 45 degrees and it's windy, most people can't handle the cold and decide not to ride. It's just too cold for them and not fun. Most can't handle the pain in their hands and have no coordination in their hands unless they are wearing some awesome gloves.
At 40 degrees, if you don't have a dry suit and a great pair of gloves, don't even try, has been my observation. You will just come back in with brain freeze and exceptionally painful hands. More than 50% of local riders don't even consider riding in less than 50 degrees. They show up, feel how cold it is, and then leave (probably wise).

The ideas being talked about on KF in more detail about cold weather kiting are that you should realize how limited your coordination and endurance are in cold weather, especially if you end up in the water for extended periods. I can attest to this. Never understatement how much danger you are placing yourself in if you are riding a half mile offshore in nuking cold front winds and you have an equipment failure in which you are basically guaranteed to be in the water for a half hour. It amazes me how fast both mental faculty and physical stamina can be zapped from your body (no matter how fit) in these conditions.
Even though the Gulf in our area rarely goes below 60 degrees, it's cold enough to zap your energy pretty quickly when submersed and exerting energy.