Ditto. I keep a bag of stuff in the trunk of my Benz, but I garage it at home and on those days I drive it to work, there is a garage there as well. If the car had to sit outside for longer than an hour in the sun, I'd leave the bag of products at home.
I used to use TW "ICE" on a different car and I'd leave it in the trunk. In a short time, the clear liquid turned yellow from the heat.