The weather service describes, "Dangerously cold wind chills as low as 25 to 29 degrees below expected." Understanding cold weather alertsExtreme cold warning: Take Action! An extreme cold warning is issued when dangerously cold air temperatures or wind chill values are expected or occurring. If you are in an area with an extreme cold warning, avoid going outside. A cold weather advisory is issued when seasonably cold air temperatures or wind chill values, but not extremely cold values, are expected or occurring.