Originally Posted by KRSW

Coming from a native Floridian, don't even worry about it. Our LOW / NIGHT temperatures are often 30c in the summer. Your equipment will be fine.

There's always a laptop or two in my trunk, a DSLR, plenty of electronic gear, no issues, and I've been keeping my gear in my car for 20+ years. My current rental car is a Jag XJ black on black, still no worries about leaving equipment in it.

The only caution I'd give you is to let batteries cool down a bit before charging them, ie: don't charge your phone whilst it's sitting in the sun on the dashboard. As long as a battery's under 40c when charging, you're fine. Even if you ignore this, most built-in charging circuits watch battery temperature and won't charge an overheated battery.