How Fast Can the Sun Heat a Car?
The sun's shortwave radiation (yellow in figure below) heats objects that it strikes. For example, a dark dashboard or seat can easily reach temperatures in the range of 180 to over 200°F. These objects (e.g., dashboard, steering wheel, child seat) heat the adjacent air by conduction and convection and also give off longwave radiation (red in figure below) which is very efficient at warming the air trapped inside a vehicle.
Shown below are time lapse photos of thermometer readings in a car over a period of less than an hour. As the animation shows, in just over 2 minutes the car went from a safe temperature to an unsafe temperature of 94.3°F. This demonstration shows just how quickly a vehicle can become a death trap for a child.
Safety Tips for Concerning Children
Make sure your child's safety seat and safety belt buckles aren't too hot before securing your child in a safety restraint system, especially when your car has been parked in the heat.
Never leave your child unattended in a vehicle, even with the windows down.
Teach children not to play in, on, or around cars.
Always lock car doors and trunks--even at home--and keep keys out of children's reach.
Always make sure all children have left the car when you reach your destination. Don't leave sleeping infants in the car ever