The National Weather Service has issued an extreme cold warning for all of Wisconsin. In southeastern Wisconsin, the extreme cold warning will be in effect from midnight on Thursday, January 22 until 1 p.m. on Friday, January 23.

Dangerously cold wind chills could reach as low as 40 below zero, which could cause frostbite on exposed skin in as little as 10 minutes.

An extreme cold watch will be in effect from Friday afternoon until Saturday morning, January 24.

"It's important to limit your time outside," Spero Gardens' License Practical Nurse and Community Relations Manager Julianne Aulenbacher says. "Dress warmly and cover up with windy conditions." 

Frostbite occurs when skin and underlying tissue freeze after prolonged exposure to cold temperatures. It commonly affects fingers, ears, toes and noses. Wind chill increases the risk, according to the Wisconsin Department of Health Services.  

Early symptoms of frostbite include numbness, tingling or a stinging sensation. As the condition worsens, skin may turn white or grayish. 

Limit your time outdoors during periods of extreme cold. Dress in loose-fitting, layered clothing and ensure that all exposed skin is covered when going outside.

Hats, gloves, and scarves help protect the areas most vulnerable to frostbite. Staying dry is also important.