Calling all Costco shoppers! The massive U.S. retailer is rolling out some changes during the holiday season, and here's everything you need to know. Just in time for the festive season, Costco Canada is introducing extended shopping hours, but only for a short period. Business Centres in Ontario will also adjust their schedules. Starting Nov. 16 until Jan. 1, the centres will now operate from Monday to Saturday from 7 a.m. to 7 p.m. and Sundays from 9 a.m. to 7 p.m.