People are bundling up across the country and many of you probably had a day or a couple of days off school due to snow and the bitter cold.
But what exactly prompts officials to cancel classes? It's because too long outside in the very cold weather and you absolutely run the risk of doing serious damage to your body.
The two big concerns are hypothermia and frost bite.
Hypothermia is when your body begins to lose heat faster than it can produce it. You may have hypothermia if you experience blue skin, dilated pupils, slowed pulse or breathing; or if you lose consciousness.
Frost bite occurs when your skin is damaged from exposure to extreme cold. With frost bite, look for numbness, a tingling or aching sensation in your extremities or blue, pale or waxy skin.