Pedestrians walk along Michigan Avenue in Chicago this week. Bitter cold is hitting much of the Northern half of the U.S., with temperatures dipping into the single digits and below zero. The extremely frigid weather is expected to last for days.
Kamil Krzaczynski/Getty Images
The National Academies of Science, Engineering and Medicine recommends that most adults get about 600 international units of vitamin D per day through food or supplements, increasing that dose to 800 IUs per day for those 70 or older.
An oil company driver fills his truck at the Sprague terminal in South Portland, Maine, last winter. This winter, costs for heating with all fuels are expected to go up.
Robert F. Bukaty/AP
Scenes from the Apostle Islands National Lakeshore in Bayfield, Wis., where Lake Superior's ice is thick enough to walk to the area's sea caves for the first time in five years.
Derek Montgomery for MPR News