It is actually the complete opposite. Life is for the most part easier in Northern climates as I explain here: https://erik-engheim.medium.com/why-are-cold-countries-richer-than-hot-countries-1751df409a21

Living conditions in southern conditions is far more difficult. You can build shelter and burn wood to deal with the cold. You can put on clothes. There is not much you can do to combat heat until the invention of air condition.