I do have some Altex which are bred to be more heat tolerant. They are large rabbits, not like a giant breed, but much bigger than say a Cali or NZ. Also, I live in North Central Texas where the stars at night are big and bright, but the summers can be just this side of hades and the bunns seem to manage. I do have a big barn fan on them when the temps get over 85.
It depends on where you are... some places are quite moderate during the summer, some not so moderate at all. I've found that where I live shade in the summer with good/great ventilation is critical.
Tamuk NZW line are more heat tolerant. They are hard to find, I have a few and love them. My SF bucks came from FL and do quite well in the heat. We all still need to remember, Heat is a rabbit killer. They do need to be checked on and watched after 90 degrees.
I do not have many of them any more for the simple reason of concentrating on my two Heritage breeds of SF & Americans.
I hope this helps.