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

President-elect Donald Trump's second inauguration will mark the coldest presidential ceremony in more than 40 years.

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.

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.

People living "basically anywhere from the Rockies eastward" will see extremely cold temperatures over the next several days, a meteorologist says.

A brutal polar vortex is set to bury the Big Apple in snow Sunday and then deliver deadly single-digit temperatures that will feel like 15 degrees below zero. New

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

Winter isn’t over yet! A polar vortex is bringing subzero winds, frigid temperatures, and possibly snow to the U.S., including snowbird states like Florida. National weather agencies and meteorologists are warning folks of a "shivering weather pattern" that’s forecasted to go into effect tomorrow and linger through next week.

Watch live as Donald Trump’s inauguration parade takes place inside the Capitol today (20 January) as Washington DC continues to be hit by freezing temperatures.

A historic winter storm is poised to produce potentially record-breaking snows from coastal Texas to northern Florida late Monday into Tuesday. The event comes as an Arctic blast affects more than half the U.