A day after a 16-month-old boy died after being left in a hot car in Burnaby, a U.S. non-profit is urging parents to never leave their children alone in vehicles, regardless of the weather.

Child advocacy group Kids and Cars said Friday the death is the first of its kind in Canada this year, adding that the tragic incident is just one example of what can go wrong when kids are left or forgotten in cars.

"The real threat here is not the heat," spokesperson Janette Fennell told CTV News Vancouver. "The real threat here is people unknowingly leaving their children alone in vehicles."

According to Fennell, a parked car acts like a greenhouse, the dashboard and seats absorbing heat from the sun that then has no way of escaping the vehicle.

That means the temperature inside the car can quickly rise far above the outdoor temperature. Kids and Cars said it has seen children – whose bodies heat up three to five times faster than adults – die from heatstroke when the mercury is as low as 15 C.

Fennell said most of the warming happens in the first 10 to 20 minutes, adding that after an hour or two, the temperature in the car can rise by double digits.

Combined with the fact that children respond differently to these changes in temperature depending on their age, Fennell said leaving a kids unsupervised is "really never a safe practice."

"The best thing to emphasize is ways to prevent children from ever being left alone in vehicles," she said. "The heat's just another reason not to do that."

According to Kids and Cars, other dangers include children being strangled by power windows, accidentally bumping the vehicle into gear or being left in a car while it's being stolen.

The organization it knows of at least seven children who have died in hot cars in Canada between 2003 and 2018. In the U.S. that number was 52 last year alone.

Because there have been cases where children are unintentionally forgotten, Kids and Cars advocates for a "look before you lock" approach, which simply means quickly opening the back door and looking inside the vehicle before you walk away.

"The biggest mistake you could make it to think this could never happen to you," Fennell said. "It can and does happen to absolutely everyone."