I've always hated anything above 24 c lol, way before I was a diabetic. Where we used to live it would get very hot in the summer and I hated it. Now I'm in a more temperate climate and the temps don't bother me.
But sugars will go up and down with temperature changes, and in heat your vessels dilate. That causes some of the issues. And sometimes it's the sudden changes in Bg levels because of a heat change that can make you feel like bunk. I can't take hot showers without my BG level shooting up and I feel horrible. So I've learned to take lukewarm showers on the cooler side so I don't feel so bad and my sugars don't climb very much. Some people hot showers make their BG levels drop.