Which would account for 5-10% of the Canadian population. Just the three metros I mentioned would account for 35% of Canadians. The record low for the coldest of those cities (Montreal) is -36F, but the average low in January is 7F.
70% of Canadians live south of the 49th parallel (the northernmost point of the Continental US) and 90% of Canadians live within 100 miles of the US border.