I don't know much about chows.
Keep in mind that some dogs coats keep them cool as well as warm. It sounds kind of weird...but with dogs with double coats the fur helps to insulate from sudden temperature changes, meaning they heat up or cool off more slowly. Also, fur protects the dog from things like insect bites and sunburn.
Also sometimes when you shave a dog with a double coat, it can take a very long time for the fur to grow back in and look as nice as it did before you shaved them. The coat can grow in unevenly making the dog look kind of scruffy for awhile too. Or you may luck out, and not have any of these issues.
Don't get me wrong, I'm not against shaving dogs. I actually keep my Papillon's fur clipped shorter, which isn't common for his breed but seems to keep him more comfortable. Papillons don't have a double coat though.
If you do shave him, make sure to still give him plenty of shady areas and watch out for sunburn. If you decide not to shave, keeping him well groomed and brushing out any shedding undercoat as well as making sure he has plenty of shade and cool water should be enough in the summer time.