Mental Floss has a post about how people dealt with extreme heat in the days before air conditioning.  Definitely read the whole thing, but since our AC went out last week in the midst of a high-90s heat wave the following paragraph holds particular relevance for our household:

Years ago when air conditioning wasn’t universal, we were sometimes miserably hot. But “miserable” is a relative term. We didn’t know what we were missing, and we were used to it.
We were never as miserable as someone in a small modern home built for
artificial climate control when the air conditioner fails!