(AREA) -- Colder weather is making its way into Michigan as crews work to restore power to the last people left without electrical service following an ice storm more than a week ago. In the Lansing area, where roughly 1,100 Lansing Board of Water & Light customers were without power Monday morning, the National Weather Service says temperatures were about 15 degrees. In the Upper Peninsula, readings of 15 below zero were reported in places. In all, about 666,000 Michigan utility customers lost power, including 40,000 from the Lansing utility. DTE Energy Company says all its 210,000 affected homes and businesses had power back as of Sunday night. CMS Energy Corporation said essentially all its 416,000 affected customers were back online.