The camcorder specs read 104 F as the top of the operating temperature range. That probably applies to guaranteed specs, and it will operate at at higher temperatures although some aspects of specs might not be met. (FWIW: the XL1 was rated 40 C guaranteed specifications, and operating to 45 C (about 113 F). It rarely gets that hot in FL. But it might in a car.

A significant issue in FL in the summer (or any other hot, humid climate, is the possibility of condensation when a cold camcorder is taken outdoors on a hot, humid day. Storing the camcorder with an ice pack while traveling just may do that. However, condensation is not an issue when taking a warm camcorder into a cold space.

How hot is the inside of the trunk? It will depend on ambient air temperature, winds, the sun exposure, and the color of the car In the passenger compartment add windows and window treatments as additional factors.

Kevin, shooting in high humidity can be a pain. I think throwing in a handfull of those little dessicant packs to your camera bag might help. Condensation can be a problem too. If you go from an air conditioned building or car out into the heat and humidity, you can get a condensation warning and shutdown. Best to go outside first, let the camera acclimate, as well as the tape, and then load the tape. I got condensation inside my viewfinder on a full size camera in Florida one time, and it stayed there driving me nuts for the whole shoot.

Kevin, If you use the set up I described, make sure you do not use ice or use a large cold pack. The other posts are correct - condensation is NOT your friend.
My setup keeps the camera at around 85 degrees on a 90-100 degree days. Any lower than that and you can start to get condensation when the camera is removed from the bag.

I know, us Northerners are so weak and spoiled! :)

It's not the heat, it's the humility... er the humidity! :)

Camera in trunk
 

Actually, not paranoid -- since the writer lives in Florida, I want to caution him the local cops who patrol some of the beaches told me thieves hang out in the parking lot watching who puts their wallet and other stuff in the trunk then break in once the victim goes out of sight. Better to do this well before you get to the beach. However, it is better to put it in the trunk than in plain sight in the car.

As far as heat goes -- Look at the specifications in the camera literature - if your trunk exceeds that, bad idea.