A mother thought it was okay to leave her two daughters in the back of a freezing cold car. It was only 16 degrees outside! The mom went into a store for 90 minutes and even found time to get her makeup done. Children that die from sweltering car temperatures in the summer and die from hyperthermia. But, children that freeze, die from "hypothermia" This happens when the body temperature becomes very low, according to Medicinenet.com. This condition can result in death.