 Am I going to be able to get that dog to the shade, keep it on the grass, or have it in an air-conditioned place, or not? And absolutely never, ever, ever leave him in the car, not even for a minute. If you have to leave that car, you need to be able to take the dog with you, or your dog should be at home. It's so much nicer to go home to a happy dog than to end up with a tragic situation by taking them with you.