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

Snow and winds are likely to disrupt traffic, trigger flight cancellations, and cause headaches for people traveling to D.C. for Inauguration Day. Baby, it’s cold outside, and it’s about to get even colder for much of the United States.

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.