The shorter your exposure to weather extremes the more you can tolerate and the less you need to be prepared. Consider some extremes of human tolerance: The 300 club. 200F (sauna) to -100F (south pole winter), naked other than foot protection. IIRC the requirement is to walk around the world in that -100F condition. Or, for very limited exposure: cryotherapy. I'm finding conflicting numbers on just how cold it can go. WebMD says some chambers go as low as -300F, although any chamber that cold your head stays outside. (That level of cold is done with nitrogen, the chamber itself will be an anoxic environment.) It's normally done with protection for all the small bits that stick out, but otherwise minimal attire.