Outside temperatures are different than inside car temperatures:

A study revealed that temperature variances of up to 20 degrees Fahrenheit occurred within just 10 minutes. Extending this timeframe to 20 minutes, the internal car temperature rose to a staggering 33 degrees Fahrenheit higher than the ambient temperature.

The Science Behind Temperature Differences:

The heightened internal temperatures in a car are primarily due to the greenhouse effect. To simplify, the sun emits invisible radiation in the form of light, which easily penetrates the glass windows of your car. The interior surfaces then absorb this radiation, releasing it back into the air as heat. While light can pass through glass windows, heat is unable to escape and becomes trapped, effectively elevating the temperature inside the vehicle.When you are in motion with the windows down or the air conditioning is active, air circulates, and the heat is forcibly expelled from the interior of your car. However, in a parked and non-running car, where there is no air circulation, the heat remains trapped.

This calculator is built based on analyses from various sources on the internet, including the American Veterinary Medical Association and the Department of Geosciences.