I have two Boxers and they do well in the heat but I would never leave them alone in extreme heat, esspecialy in summer. I always keep a close eye on my dogs... hot days or not. And provide PLENTY of water. Chinese Cresteds get sunburnt easy, so definetly not a Chinese Crested. Fluffy or long haired dogs, such as Malamutes, Huskies, various retrievers, Pomeranians, and others. Bald breeds such as some Poodles and Chinese Cresteds are not good for heat. But otherwise, any dog would do good in heat as long as you keep a close on on them