I didn't realize that it could get so hot even in moderate temperatures. Scary!
I would never leave Thor in the car anyway, because I think he is so cute and could be stolen easily. I *always* take him with me, even for those "two minute" errands. Keep that in mind too, even if your car is not hot at all, leaving your yorkie alone is like leaving a $500 piece of electronic equipment in the back seat.
I'm glad I live in SF where it doesn't get too hot.