My pugs do fine, but it’s not like I live in a hot place. Still, it gets hot here in the summer - last summer we had a few days in the hundreds, and it’s supposed to be 95 here today. I keep an eye on them when it gets hot, but it’s more along the lines of not leaving them outside in the middle of the day for longer than it takes to do their business, or taking them for long walks in the heat of the day.
Our house is not air conditioned, except for a couple rooms with window air conditioners. Right now I’m sitting in my air conditioned office with the door open, and the pugs choose to sit in the non-air conditioned room outside my door. They seem fine.
When it’s really hot, I put ice cubes in their water dish. They seem to like that.
Overall, the cold seems to bother them more than the heat.