It’s not unusual for winter temperatures in South Dakota to be at or below zero. It’s also not unusual for the wind to blow. When certain criteria are met, the National Weather Service issues a wind chill warning.
Weatherology meteorologist Megan Mulford says a blast of Arctic air has moved into the upper and central Midwest.
She says calculating wind chill involves a complicated mathematical formula.
While it’s extremely cold outside, Mulford says the area has been colder.
