(KAIT/NBC) - It's a warning for all parents as we head into summer: check your backseat.
In 2017, 43 children lost their lives in hot cars.
Nine have died this year, with two just this week alone.
A nine-month-old Houston, Texas girl was trapped for hours inside a truck to die in the heat. One parent thought the other had brought the child into the house, but that wasn't the case.
Just one day earlier in Indiana, a three-year-old died after she spent two hours in a closed car, also an accident.
Safety expert Janette Fennell says there is never a good time to leave your child in a car, even on days when temperatures are in the 70s. Inside the vehicle can be well over 100 degrees in less than a half hour.
"We've done a great deal of education and raising awareness but you can't train your brain not to forget," Fennell said.
Even responsible parents can forget, which is why advocates continue to push for alert systems in cars.
Click here for more safety information this summer.