Honestly, I've never had an issue with it. I had my first husky, Misty, when I lived in Houston, Texas. It's HOT there. She was a 70% outside dog, 30% inside dog, and she really never had any problems. Their coats really aclimate to what weather they're in. Misty never really developed much of an undercoat so she didn't have much to shed off. Her coat stayed really short and cool most of the year because it never got very cold. In the cooler winter months, she had a bit of an undercoat, just enough to keep her warm, and then it shed off pretty quickly when it started to get hot again. She had lots of shade and lots of water, and access to the air conditioned house. We never had a problem with the heat.
We now live in Tennessee, and we've had two huskies here. It gets in the 80's-upper 90's here in the summer, and again, we haven't had a problem. Both Holly and Violet have been 99.9% indoor dogs (only outside for exercising, play, going potty) and we keep our house nicely air-conditioned. When we take the dogs out in the summer, we just prepare accordingly. We are sure to bring water, go to a decently shaded place if not indoors, etc.
I don't see an issue with having northern breeds in hotter climates. You just adapt to keep them happy, just as they adapt to keep themselves happy. It's not uncommon to see huskies in places like Florida where it can get very hot and humid.