If your goal is sightseeing, comfort and a good overall first impression of the Northwest Territories, the best times are usually July and August, early September, and March. Each gives you a very different North.
July and August
July and August are best for general tourism. This is when roads, lakes, trails and remote lodges are most accessible, and it is the easiest season for fishing, paddling, wildlife viewing and flightseeing.
It is also the main window for places like Nahanni, where access and guided travel are at their most practical.
Early September
Early September is one of the smartest choices for many travellers. You can still get decent conditions, but with darker nights returning, it becomes a strong time for northern lights around Yellowknife.
March
March is another excellent pick, especially if you want winter scenery, aurora viewing and northern winter events.
Choose the North you want
Realistically, the NWT is not a casual add-on destination. Distances are huge, services can be limited and weather can turn quickly. But if you go in the right season and match your expectations to the region, it can be one of the most memorable trips in Canada.
Focus on Yellowknife for aurora and culture, Nahanni and the Dehcho for wilderness adventure, and Great Slave Lake country for fishing, boating and big northern scenery.