TEXAS (KETK) – Summer officially started just one day ago, but hot car child fatalities are already an issue.

Officially called “pediatric vehicular heatstroke”, more than 900 children have died of it since 1998. Each year, an average of 38 children die in hot cars— during the summertime, that’s almost two per week.

So far this year, five children have died in hot vehicles, and two of those were in Texas exactly one month apart from one another. One child, a 10-month-old girl, died in a Houston-area hospital after being found in a hot car outside her home on May 20. Then on June 20, a 5-year-old boy died in Harris County outside his family’s home after being left in his car seat for a few hours.

Most studies report that the leading cause of leaving children in vehicles is forgetfulness by the caregiver, and most of those deaths involve children under 2 years old.

According to the National Highway Traffic Safety Administration, a child’s body temperature can rise three to five times faster than an adults, and heatstroke begins once the core body temperature reaches 104 degrees. A child can die when their body temperature hits 107 degrees.

The National Weather Service shared graphics depicting how temperatures rise in a car on an 80 degree day. After 10 minutes, the temperature inside the vehicle grew to 99 degrees. After half an hour, the inside temperature was 114 degrees. After an hour, the vehicle was 123 degrees.

And no, cracking or rolling down windows isn’t a sure way to keep your child safe.

“Because of the way the sun heats the car up, it’s a radiation energy, it’s almost like a greenhouse so your car just absorbs the heat from the sun,” Dr. Tiffany Turner, a pediatrician at CHRISTUS Good Shepard Medical Center in Longview, told KETK. “Tinted windows help, but they don’t do enough.”

Fore more information on hot car deaths, click here.