This can be a touchy subject. I for one do not mind if you leave you dog out 24/7 IF the pet has no other choice AND is taken care of PROPERLY.
BUT it also depends on the breed too. Any dogs with shorter muzzles (pugs, boxers etc...) can have difficulty breathing especially in hot weather. Those breeds should not be kept outdoors.

If the dog has shade available all day long, FRESH clean water, shelter, dry insect free food, preferably a small kiddie pool for those really warm days (at least above 85), keep the area CLEAN and gets enough attention & exercise I see no problem with keeping a dog outdoors. After all that is a heck of a lot better than being on death row in some shelter or having a home with a crappy owner.

But if at all possible please try to keep the pets indoors in the a/c or somewhere cool (basement etc..) when it gets above 90 and please do not leave your pets outdoors when it gets very cold.

But personally me myself I would NEVER keep an animal outdoors all the time. Dogs are pack animals they need their human family. I believe to treat others as you would like to be treated... no matter what species or breed. Would you like to live where you keep your dog?