Arctic air over the northern United States made the city even colder Wednesday night, with wind chills making it feel below zero overnight.

After 3 a.m., the wind chill in the city was projected to fall under zero degrees — and as low as -3 by 8 a.m.

Thursday, temperatures will struggle to get out of the teens, with wind chills of single-digits expected.

High temperatures in the low-20s are slated Friday. It will warm up a bit Saturday, before the temperatures fall on New Year's Eve.

People planning to watch the ball drop in Times Square on Sunday should expect for bitter cold and wear many layers and cover up any exposed skin to avoid frostbite, which can occur in about 30 minutes. Your extremities are the body parts most susceptible to frostbite.

Health officials are urging all New Yorkers to take precautions, especially since this is our first cold snap of the season and our bodies have not adjusted to the change in temperature yet.

The city is working to get homeless people shelter as temperatures dip and the city faces its coldest air of 2017.

The Department of Homeless Services has issued a Code Blue warning. That means outreach teams are scouring the streets to make sure people find shelter.

The city is asking New Yorkers to call 311 if they see anyone staying in the street.

During a Code Blue, the city's shelter system cannot deny anyone brought in by an outreach team, and will accommodate walk-ins.