I live in Tennessee and our summers get pretty dang hot. The first year I had my Pyr, I didn't shave her and she panted to the point of concern. Her sides would heave and a few times I got so worried that I applied a cold compress to her underbelly. This reaction was caused by a 20 minute walk. Not wanting to face the same thing the following summer, I had her shaved and voila! No scary panting. Her coat grew back fine and I can't tell a difference in the quality and thickness. I think you just have to use common sense on this issue. If you shave your Pyr, don't leave them outside in direct sunlight for hours as that will give them sunburn. Treat a shaved Pyr as you would a child as far as protecting their skin. Also, make sure the coat has plenty of time to grow back before winter if they are outside dogs. My dog's coat grew back in about 4 months. A lot of people will tell you that is is sacrilegious to shave a Pyr, but it saved my dog a summer of hot spots and forced inactivity. With her hair long in that first summer, we couldn't go on walks morning, day, or night. Shaving her greatly increased her quality of life. Just be reasonable and keep the pup out of the sun.