The softer the child and the warmer the day - the faster the damage happens. Temperatures in a closed car in the sun can soar within a short hour to a state that does not allow the body to cope.
Every year, children die as a result of car forgetfulness - an unnecessary death, which could have been prevented. Make it a habit to leave your bag in the back seat or your phone that you don't need to touch on the road anyway, or any other method that will make you check the back bench at the end of each trip.