Lowest wind chill early Friday morning was in Pensacola. While 21 may feel cold, compare it to -17 in Omaha, Nebraska.

Cold air originating from the Arctic Ocean was dislodged earlier this week and spilled south across the United States. As a result, wind chills across the Eastern Plains bottomed out around 30 degrees below 0.

Wind chill temperatures are how cold people and animals feel when outside. It’s based on the the rate of heat loss from exposed skin caused by wind and cold, according to the NWS. Essentially, as wind increases, it draws heat from the body and drives down skin temperatures and internal body temperatures.