U made me shiver ! I am not accustomed to such a low but currently at 5°C is the one of least I faced. There are colder region like the northern parts but never been there, the temperature gets low as below as -20 or more. The important is to adapt. I am sure people out their prepare for such temperature in advance. I have been to high temperature region and easily bear close to 50°C. It is all in our mindset to prepare ourself to adapt to such situation.