A combination of factors has trapped winter's cold air over Canada and Alaska, making for unseasonably warm weather in the Lower 48.
The temperature in Minneapolis didn't fall to zero degrees this winter until Jan. 12. On Jan. 5., the daytime high in Rapid City, S.D. (a record-setting 71 degrees), was higher than in balmy Miami (69 degrees). And just a couple of days before New Year's, visitors to Park City, Utah, skied on man-made snow and dined al fresco — without their parkas.