Inuvik, NWT, with a 2021 census population of 3,137 is the fifth largest settlement in Northern Canada (north of the 60th parallel). At "only" 68°22′ north, it doesn't even quite make it to Wikipedia's list of northernmost settlements. But that is the most populated town in Canada whose antipodal point lies within the continent of Antarctica. The antipodal point is the point you would get to if you could drill directly down through the centre of the Earth and come out the other side (also, it is the most distant point on the surface of the Earth, which is always approx. 20,000 km from the original point). Yellowknife and Iqaluit, the capitals of the Northwest Territories and Nunavut, respectively, have antipodal points that lie at sea close to the Antarctic mainland, within a few hundred kilometres from shore.
I found that interesting because while Inuvik is certainly cold most of the time, it's still surrounded by a lush boreal forest and the warmest couple of months of summer are fairly pleasant. I've personally never been, but a friend of a friend lived there for years and still goes there. The antipodal point though is a white desert. About 300 km from that point, on the much milder coast (the antipodal point itself is more than 2000 metres above sea level), one finds Dumont d'Urville Base, a a French scientific station, which is completely barren of vegetation and is barely above freezing during summer (at least they have penguins).
The reasons for the difference in climate are many, but the Antarctic Circumpolar Current is probably mainly to blame, together with the high elevation of the surface and high albedo of the ice.
While 50 is north enough and the absolute majority of Canadians live south of it, "Northern Canada" generally refers to the three territories (as opposed to the ten provinces), that start at 60 (mostly, there are some islands south of that).