Vehicle Heating Dynamics
The atmosphere and the windows of a car are relatively “transparent” to the sun’s shortwave radiation (yellow in figure below) and are warmed little. However this shortwave energy does heat objects that it strikes. For example, a dark dashboard, steering wheel or seat temperatures often are in the range of 180 to over 200 degrees F.
These objects (e.g., dashboard, steering wheel, childseat) heat the adjacent air by conduction and convection and also give off longwave radiation (red) which is very efficient at warming the air trapped inside a vehicle.
Objects Heated by the Sun Warm Vehicle's Air