Winter came early this year with November temperatures averaging 20 to 30 degrees below normal. Here's how cold it needs to be for schools to close in Wisconsin.
Most schools close once the windchill hits -35, as advised by the National Weather Service.
Wind chills of 30 to 40 below-zero can cause frostbite in 10 minutes or less. Wind chills of -25 cause frostbite within 15 minutes. Without protective clothing, hypothermia is possible and even death.
Milwaukee's coldest temperature so far this season was 9 degrees on Nov. 12.