Cheeks flushing or vasoconstriction: When temperatures hit 50 degrees, your blood vessels narrow to reduce blood flow near the body’s surface. Sometimes the blood vessels dilate and burst, which causes redness. This can also numb your hands.
Runny nose or cold-induced rhinorrea: At 45 degrees or below, cold and dry air causes difficulty for your lungs. Your nose wants to moisturize, but it can overcompensate and cause it to run.
The more dangerous symptoms follow:
Shivering caused by cold or oscillatory muscular activity: Your core body temperature has dropped about a degree below its normal temperature around 98.6 degrees. This can be the first sign of hypothermia. At 96 degrees, your motor coordination begins to fail. Body temperature of 90 degrees is immediately life-threatening.
Frostbite: Happens when temperatures and windchills are above zero, but at -18 the threat is much greater, and it can happen on exposed skin in about 20 minutes. At -50 degree windchill, frostbite can happen in as little as five minutes.