CHICAGO (CBS) —  The intense heat poses a big risk to young passengers inside cars already this year, 21 kids in the U.S. who have been left in a hot car have died.

But on extremely hot days, the danger increases exponentially.

A car’s temperature will increase up to 40 degrees in an hour if left in the hot sun.

That’s an 80% increase in just 30 minutes.

So if it’s 95 degrees, within 10 minutes, it can be 114 inside the car. Within 30 minutes, it’s a scorching 129 degrees.

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