I do not think the closed or covered cockpit is an issue in Florida. Most of the kayaks I have seen down there have the covered cockpit. The hull is in the water so only the top of cockpit will get hot. Also keeping the inner hull covered should make it cooler unless there is a skirt or cockpit cover that seals the cockpit and stop air circulation.

���Florida kayaking in the summer takes some modifications. 1. Don't wear cotton. Wear synthetics known for rapid drying. You can wet you shirt for example and stay cooler. 2. Wear a hat. Dip it in the water. So on the head evaporation will keep you cooler. 3. Closed decks are not a problem until the skirt is installed. 4. Kayak the spring runs in summer, 72 degree water vs 80 degree.

���5. Don't kayak in the middle of the day. Think sunrise and night. Find a club and go on a biolumenessice paddle, cooler and just cool. Operator error is a bigger problem than decked over boats.

���See, http://www.meetup.com/kayaking-130/events/223417482/