Yeah, I wouldn't say I enjoy riding in the heat. Thyroid disease has caused problems with my heat tolerance. I just did it gradually and methodically this past summer to find out how much I could tolerate if I did it carefully. About 15 years ago when I hadn't yet been diagnosed with thyroid disease and treated, I had a bout with heat exhaustion and passed out while working outdoors in summer heat. So I've been very careful since then.
I got a late start on a couple of metric centuries this past summer, so I had to stop at a park with covered picnic tables and rest for about 30 minutes. That spot is at the peak elevation of that particular ride, so it's a convenient place to cool off before tackling the relatively easier return route. But it's all roller coasters so it always feels like climbing even though it's a gradual change in elevation over long distance.
Usually I prefer night rides in summer, unless I can get a really early start. If I don't start before 9 am it's gonna be hot well before noon.