However, a deep freeze, thanks to the polar vortex dipping down from Siberia, is bringing an even harsher arctic blast to million Americans this week. Maps show what to expect as the cold front ...

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.

The temperature is predicted to be around 22 degrees during the swearing-in, the coldest since Ronald Reagan’s second inauguration.