There have been a number of 9-1-1 calls from people walking by cars and pickups with dogs especially inside sun-heated vehicles. Hyperthermia can kill an animal very quickly. And is many instances, leaving a window “cracked” is not going to save them. Under just about any circumstances, leave your pets at home. They don’t need to go for a ride and then perish on the seat of your vehicle.
So, use common sense. More than 5 minutes – they’re starting to suffer. If you REALLY love them, leave them at home.