When the temperature outside is 100 F or above the Temperatures inside the car can quickly climb to 170 F to 240 F within about 5 minutes.
I did this experiment with my own car out in the sun while I went shopping at Walmart when it was 100 F outside.
I parked directly in the sun and went inside after setting a thermometer in the car.
When I came back to my car after 20 minutes of shopping the inside of my car got to 240 F which is dangerously hot and can kill a pet or child or anyone in minutes.