Using historical climate data this interactive map created by Plantmaps covers the province of Northwest Territory which ranges from Zone 2a to Zone 7b.
Hardiness Zone 2a-40°F to -45°F | 
                    Hardiness Zone 2b-45°F to -50°F | 
                    Hardiness Zone 3a-50°F to -55°F | 
                   
Zone 1b-55°F to -50°F | 
Zone 1a-60°F to -55°F | 
Hardiness Zones, Gardening Zones, Growing Zones and Plant Zones refer to defined geographic regions that can support specific plants, flowers and trees. The zones define a minimum range of temperatures that a plant or tree can survive safely in that zone. The most commonly used Hardiness Zones were defined by the USDA. This map applies the USDA hardiness zone classifications to zones in Canada derived from historical climate records available from the National Climate Data Archive.
Fort Franklin - Hardiness Zone 2a
Fort McPherson - Hardiness Zone 1b
Fort Reliance - Hardiness Zone 2a
Fort Simpson - Hardiness Zone 2a
Fort Smith - Hardiness Zone 2a
Hay River - Hardiness Zone 2b
Inuvik - Hardiness Zone 2a
Liverpool Bay - Hardiness Zone 2b
Norman Wells - Hardiness Zone 2a
Rae - Hardiness Zone 2a
Snowdrift - Hardiness Zone 2a
Tuktoyaktuk - Hardiness Zone  
Yellowknife - Hardiness Zone 2a