When you don't live in constant AC you can tolerate a surprisingly wide range of temps. Houses were also built to have better airflow and adaptability (removable shutters, awnings, textiles, isolated room heating, etc...). There was also more emphasis on personal temperature regulation: layering, hats, airy/sun blocking robes, heated stones, hot water containers, etc...

Outside of extreme weather events, people were probably just as comfortable but with more inconvenience.