The deepest of deep freezes yet this winter in Minnesota hung around for a second day Tuesday, with the temperature plunging to as low as minus-36 in Embarrass this morning.

The frigid temperatures and dangerous windchill readings are allowing some students a modest extension of their long Martin Luther King holiday weekend.

Dozens of school districts around the state -- but not in the Twin Cities area -- pushed back the start of classes two hours to give Mother Nature a chance to warm things a bit. Those districts include Albany and Alexandria in western Minnesota, Bemidji and Cass Lake-Bena in the north, and Holdingford, Little Falls and New London-Spicer in central Minnesota.

Several districts ringing Duluth called off school altogether. They include Hermantown, Proctor, Cloquet and Carlton. Just before sunrise, the temperature was 20-below zero in Duluth, with a windchill reading of minus-43, according to the National Weather Service (NWS).

Among the high school sporting events in the Duluth area scrapped for Tuesday night: boys hockey at Duluth Denfeld, and boys and girls basketball games at Duluth East.

To the north and west of Duluth, the mercury has fallen to 36-below in Embarrass.

Star Tribune, Star Tribune
With temperatures below zero Tuesday morning, the skyways above Nicollet Mall were crowded with commuters.

In the Twin Cities, the NWS reported a low of minus-11 at the Minneapolis-St. Paul International Airport at about 7 a.m. Tuesday's high will struggle into positive territory by afternoon to 1 degree.

Monday's high in the Twin Cities of minus-2 came at 12:20 a.m., marking the first time in four years that a day's warmest reading remained in negative territory.

There were about 900 calls to AAA because of cars that wouldn't start or tires that went flat, about double the volume for an average Monday, the travel service provider reported. That total came on a day when many government workers had the day off for the MLK holiday and nearly all schools were closed as well.

As the week progresses, highs will warm to about 11 or so, with modest chances for snow, according to the Weather Service.

Paul Walsh • 612-673-4482