President-elect Donald Trump's second inauguration will mark the coldest presidential ceremony in more than 40 years. Washington is forecast to reach only the mid-20s for a high temperature, along with gusty winds.

The most unusually cold air in the Northern Hemisphere will be over the United States early next week, bringing dangerously frigid conditions.

The polar vortex is a ring of cold air that typically circles the Arctic. A strong jet stream essentially acts like a fence, keeping it locked there. If there's any weakening in the jet stream (the fence), the frigid air can become unstable and spill out. This sends the normally trapped cold air much farther south.

Sen. John Fetterman (D-PA.) arrived at the U.S. Capitol for President Donald Trump’s inauguration sporting his trademark Carhartt hoodie and gym shorts, drawing criticism from both conservatives and liberals online.

A rare winter storm is getting set to slam the Gulf Coast and South, with cities from Texas to Florida under Winter Storm Warnings.

Some areas of the U.S. may see temperatures as low as -20 or -30 degrees early next week as arctic air from Siberia rolls in.

A lobe of the polar vortex will swirl into the United States. (Video: Ben Noll/The Washington Post) Temperatures will dip dangerously low, reaching minus-20 to minus-30 in parts of North Dakota ...

A polar vortex is slated to sweep most of the continental US bringing winter storm warnings and a hazardous freeze to millions.

As President-elect Donald Trump is set to return to the White House on Monday (Jan 20), his inauguration will mark the coldest presidential ceremony in over 40 years as the polar vortex is headed to Washington.

Follow live updates from Donald Trump's presidential inauguration as he is sworn in as the 47th US President to succeed Joe Biden.

Follow live updates from Donald Trump's presidential inauguration as he is sworn in as the 47th US President to succeed Joe Biden.