Get ready for a "polar plunge": the first week of winter in the US brings snow and extremely cold temperatures

Storm system affects millions in the US 1:32

(CNN) --

Winter in the United States officially begins this Wednesday, and the cold will arrive in full force.

Temperatures will plummet this week, and even Florida won't be spared, thanks to a strong high-pressure system sliding south from Canada.

“Very cold air masses from the Arctic will engulf much of the central and eastern half of the nation over the two-week period, including the busy holiday travel season,” the Climate Prediction Center said.

From Idaho to Minnesota, temperatures will range from 10 to 30 degrees below average starting this Sunday.

By this Tuesday, that bitter cold will stretch from Washington to Wisconsin and down through Texas, becoming more extreme, with some areas reaching 45 degrees below normal.

• The cold makes its way across the United States from coast to coast as winter begins to take hold

"Highs will only reach single digits (Fareinheit) in the northern Plains, while lows will fall into subzero territory and below 10 and up closer to the Canadian border," the Weather Prediction Center said.

“Gusty winds will make it feel even colder throughout northern Montana, where wind chill advisories are in effect due to the possibility of wind chills as low as 30 to 45 degrees below zero.”

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At those temperatures, hypothermia can begin in less than 10 minutes, but could be as little as five minutes in areas of South Dakota.

The National Weather Service office in Rapid City, South Dakota, said wind chills as low as 50 to 60 below are possible Wednesday night.

Credit: CNN Weather

Worse yet, the wind chill advisory is in effect through Thursday.

Five full days of freezing temperatures to kick off the winter season, and it's not just for Montana.

cold start of winter

It's that time of year again when everyone hates Florida — the only really warm place in the entire country — but only for the next few days, as Florida will also cool down by the end of the week.

This Monday, Atlanta will see a high near 50 degrees Fahrenheit, but on Friday, that high may not even reach 30 degrees.

Denver goes from a high of 46 degrees on Monday to a high of just 14 this Thursday.

Some Floridians will see a much more sudden drop.

Pensacola's high temperature of 64 on Thursday will look downright tropical compared to a high of 38 just 24 hours later.

And yes, this means overnight low temperatures are likely to drop below freezing.

Be sure to cover any plants you still have outside and bring your pets inside this week.

Even Miami's high temperature of 73 on Friday — likely to be the hottest place in the continental US — will be nearly 10 degrees cooler than the day before.

• Snowstorms in the US: in which states will they occur and how long will they last?

Over the next week, more than 260 million people will see freezing temperatures in the US, more than 80% of the population.

“As cold as it is, it will be difficult to challenge the daily record lows/maximums because this event overlaps with parts of the historic 1983 and 1989 cold snaps. At the very least, parts of the East may end up seeing the coldest temperatures for any December since 2017”.

The cold air is here to stay.

Long-range forecast models continue to show temperatures well below normal over the Christmas weekend.

Credit: CNN Weather

“A major storm system is forecast to affect much of the country before Christmas Eve, with widespread wind gusts, areas of heavy rain and heavy snow, as well as bitter cold in its wake,” the Prediction Center said. Meteorological.

"Be sure to pay close attention to this week's forecast as the details become true."

If you're looking for warm weather for the holiday weekend, you'll be limited to South Florida, Southern California, or Hawaii.

CNN Meteorologist Haley Brink contributed to this story.

US Winter Forecast