Cold and winter.( no expert but i do have to deal with cold every year) -30C or -22F
Humans (other animals) are warm blooded. Our core body temperature is meant to be around 98.6F or 37C . If it falls below a certain level, one can go into hypothermia (lack of heat) Other conditions like freezing of the skin can occur in below freezing conditions. Numbness of the skin, frost nip and frost bite. Frost nip is like a 1st degree burn close to the surface (pins and needles) Frostbite is more like a 2nd/3rd burn be like where tissue/muscle starts to freeze and skin color changes( red, white and black) The longer someone's been in the cold. The more time is needed to "warm" them up. Keep the body moving toes, fingers and such. Metabolic heat will help but after a while you will get tired. One can't shiver forever.
I tend to say dress for winter in layers. Smaller spaces tend to warm up faster. Dead space or a warm layer of air can keep one good for a while . Wick, insulation and wind/water proof layer. If one gets too warm, they can open/remove a layer for a short time. I tend to wear mitts over gloves.(or both) Fingers together stay warmer then when apart like a glove. Cotton is big No No in winter. Wet cotton dries slow and water will take heat away faster the air but slower than say " metal" like a shovel. Be comfortable. "just right" Avoid sweating /getting wet. Drink some water as thick blood flows slower and blood "is warm" Windchill ( wind blowing heat off the body) Find cover away from the wind. 50km/hr arctic air in -30C can be "harsh"
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