There is a debate amongst archaeologists about whether the first hominids in Europe were clothed or not. Living in a centrally heated house fully clothed, it is quite hard to imagine surviving all day outside naked even in the (Scottish) Summer let alone winter. However, it is reported by explorers to S.America, including Charles Darwin, that there were natives in Tierra del Fuego (S.Chile) who lived their lives naked in a climate where it appears winter temperatures go down below freezing. However, I'm not sure about this. What images are available often show the natives with blankets, but there were several tribes and only the ones on the coast were said to be entirely naked. But it is also possible that even this tribe were only fully naked in Summer, still quite remarkable, but it might be they only happened to be naked at the time of year when explorers passed by.
So, I thought I would ask modern naturists, what is the lowest temperatures that they could spend the entire day outside (although natives had small huts and fires, so perhaps a few "coffee breaks" warming up would be allowed.
I also assume it takes time to cold adjust?
All help or insights would be gratefully accepted.