A polar vortex dipping down from Siberia will bring a cold front with frigid temperatures to nearly 300 million Americans. See maps of the arctic blast.

Most of the current cold snap, which swept in a few days ago, should have passed, but temperatures remain dangerously low. Experts anticipated that today (Tuesday) and last night would be the coldest of the spell,

Still, several Colorado school districts will start late on Tuesday as the state waits out the last of subzero temperatures. Denver, Jefferson County, Aurora, Littleton, St. Vrain Valley and Weld, among others, are all on a two-hour delay.

Marylanders are bracing for the upcoming polar vortex, expected to bring temperatures into the single digits early this week. And state workers are out and getting ready for the freezing temperatures.

A disruption in the polar vortex is about to send an Arctic air mass from Siberia as far south as Florida. Yes, Siberia—and it’s as dramatic as it sounds. As many as 47 states will experience unseasonably cold temperatures. Some areas will be hit with dangerous wind chills as low as 40 below zero.

According to the National Weather Service, a polar vortex will impact most of the country this weekend, here is what you need to know.

A new blast of Arctic air sweeping from north to south will bring bone-chilling temperatures to millions of Americans this weekend and next week.

AVERAGE LOW FOR JANUARY 18th: 15° SATURDAY’S SUNRISE: 7:32 AM SATURDAY’S SUNSET: 5:04 PM Elmira, N.Y. (WETM) – A polar vortex brings in freezing temperatures into the work week. Otherwise, we will see a lot of sunshine for the work week.