Another day of freezing cold weather gripped the upper Midwest and northern plains. In Alamosa, Colo., the temperature hit 31 degrees below zero, the nation's coldest overnight temperature for the second straight day. It was 25 below at Butte, Mont., and 14 below at Elizabeth, Ill. Wind chill readings remained below zero across much of the upper Midwest and northern plains. A blast of arctic air on New Year's Day gave many cities their first subzero readings this winter. In Superior, Wis., the temperature was 2 degrees in the morning, with a wind chill of 30 below. The wind in Chicago again drove temperatures down to the equivalent of 17 degrees below zero, and many emergency warming centers, opened New Year's Eve, remain filled to capacity. Ohio was hit with its coldest temperatures of the season, with readings in the single digits in most of the state's major cities.