However, a deep freeze, thanks to the polar vortex dipping down from Siberia, is about to bring even harsher arctic blast to nearly 300 million Americans starting this weekend. Maps show where and when the cold front will arrive.

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

The polar vortex is expected to reach the Utah-Idaho border sometime in the late afternoon and evening Friday as it continues to move south. As it moves through parts of the state, it will produce small snow showers, bringing more snow to the region before drier conditions return.

Snow and winds are likely to trigger flight cancellations and cause headaches for people traveling to DC for Inauguration Day.

A blast of Arctic air is set to cover much of the United States with temperatures below freezing starting on Friday and into next week, impacting millions of Americans in nearly all of the contiguous states.

Dangerous temperatures are sweeping the country, with 100 million people from the Plains to the Northeast feeling the chill. Even those in the South will see some effects. Several cities have already declared weather emergencies,

These severe cold events occur when the polar jet stream – the familiar jet stream of winter that runs along the boundary between Arctic and more temperate air – dips deeply southward, bringing the cold Arctic air to regions that don’t often experience it.