My dog is a bc. He rides with me everywhere but he loves the winter for some reason. That whole back end of my SUV is like a giant play room for him. All toys, some bones, and a small comforter. I am always concerened that one day a person is going to see my Buddy and smash the windows in the car in summer when the air is on. Or winter when a little bit of heat is on. And yes I will say it i am a big pushover for animals.
The Australian law is no more than ten minutes on a day over 28 Celsius.
That said for me it depends on the dog and how the dog is feeling right then. My dog is half Chihuahua, he’ll lie on the concreted in the backyard on 40+ days when everyone is posting about how it’s dangerous for dogs to be out in the heat. I’ve known a bunch of kelpies - Australian working farm dogs - that are just fine in the heat as long as it’s not extreme.