What Is The Coldest Temperature A Rabbit Can Stand What Are Dangerous Temperatures For Rabbits?

What are dangerous temperatures for rabbits? - what is the coldest temperature a rabbit can stand

I have 3 rabbits, kept in enclosed spaces. My friend and I got a run / hutch combo for them so they can outside if the weather is nice and feed them and play. They stay inside when it rains, it gets very hot, etc. but I am told that rabbits should be at temperatures above 80 degrees. Is that true? And what is the coldest temperature that is still safe to go?