Dude! The buckle. LOL!
Well, since the car is always in the garage the seat buckle never gets hot. If I go somewhere I rush in and rush back out to the car before it has a chance to get hot.
And here is a tip I learned long ago: When you first get into a hot car and turn on the air conditioner, crack a window as you drive and that sucks all of the hot air out of the car. It gets much cooler, much faster. After the car cools down, close the window.