Mountain Daylight Time ( MDT ) = GMT-6
Northwest Territories is in the Northwest Territories Time Zone in Canada, which is in the Mountain Time Zone; 7 hours behind Greenwich Mean Time (GMT-7).
Like most provinces in Canada, Daylight Saving Time is observed in Northwest Territories, where the time is shifted forward by 1 hour, resulting in a 6 hour difference behind Greenwich Mean Time ( GMT-6 ).
After the Summer months the time is shifted back by 1 hour resulting in the normal 7 hours difference behind GMT.