Children Hot Car Heat Stroke
Getty Images/The Washington Post/Contributor

As a sweltering “heat dome” continues to invade much of the east coast, organizations are sending reminders to stop leaving pets and people in cars.

A 3-year-old died on Sunday in Far East Dallas, Texas, marking the 21st child to die in a car in the United States this year.

That number is up from 11 children who died at this time last year. In total, 25 children died when they were left in cars last year, according to a press release from Kids and Cars, a public safety awareness group that tracks heat-related child deaths in vehicles.

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The child was left in the car while his father went to a Bible study at a local church in the Dallas area, where temperatures reached 98 degrees on Sunday, according to the Washington Post.

The 3-year-old wasn’t the only child killed after being left in extreme heat in a car this weekend. A 4-year-old died in Williamsport, Pennsylvania on Friday after she was left unattended in a car for several hours, the Washington Post reported.

The child was supposed to be taken to daycare, but the caregiver forgot and went to work instead.

Temperatures reached 97 degrees on Friday in Williamsport.

According to AccuWeather, temperatures are expected to be higher than 90 degrees every day this week in cities like Washington, D.C. and New York.

Researchers say that even if it is 87 degrees outside, car interiors can still reach unbearable temperatures of more than 140 degrees.

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According to the National Safety Council, temperatures in a car can increase by 19 degrees after just 10 minutes of being in the sun, and they can increase by 34 degrees after 30 minutes. Car interiors can get 50 to 55 degrees hotter than outside temperatures when sitting in the sun for more than 2 hours.

The National Safety Council says to never leave a child unattended in a car. If you see an unattended child in a car, call 911 immediately.