Multiple rounds of frigid Arctic air could sweep across the eastern half of the U.S. in the coming weeks, ushering in an unusually cold start to 2025.

The first bitter cold snap will hit the northern Plains and Midwest on Wednesday and Thursday, then reach the Northeast late this week.

The rise in Arctic air is likely to be the start of several successive cold blasts that will last through most of January, triggering freezing temperatures across much of the country.

Starting next week, the polar vortex will likely trigger even colder air across the eastern half of the United States

The polar vortex lives in the upper atmosphere and is located near the North Pole in the Arctic. When the polar vortex is strong, it traps cold air in the Arctic. As the polar vortex weakens or dissipates, it releases cold air southward.

The eastern half of the U.S., particularly the East Coast, will likely see below average temperatures for most of January.

It’s too early to say exactly how cold it will be, but millions of people could experience dangerous temperatures below freezing.

With cold temperatures increasing, there is a chance that many places will see more precipitation as snow rather than rain.

A large, fast-moving storm could bring snow to parts of the Midwest and severe thunderstorms to the South early next week. Some of this snow could also reach the mid-Atlantic.