Before posting here obvious things like “don’t leave children in a vehicle,” please read this article: Fatal Distraction: Forgetting a Child in the Backseat of a Car Is a Horrifying Mistake. Is It a Crime? It is really good, it won a Pulitzer Prize for a reason.

Spaniards, repeat after me: don’t leave small children in closed extremely hot boxes. Because it is hot inside of hot boxes. Do you want to be forced to have inscriptions about it like Americans do? “Attention! This hot thing is hot, especially when it is hot. Hot is bad. Hot boo-boo.”

I would say that you don’t leave any living being in the car, which is not capable to opening the door with ease by itself, when temperatures are elevated outside!!! This counts for elderly, immobile or physically or mentally disabled people as well as for any animal - dogs die often due to leaving them alone in the car when it’s hot, sometimes the window slightly open, though this does not help.

So, please, take action if you see anybody or any animal suffering in a car, because it is hot. In some countries you can call the police.