Canadian here. This may be true for some (many) parts of Canada but certainly not all of Canada. For example, with proper gear you can run outdoors in Vancouver year-round. When I lived in the GTA, I routinely ran outdoors through late December and almost always resumed by mid-March.

Point being: dressing appropriately can extend your running season dramatically.

Even in your example, there's a 4 month period where it's impossible. Snow + ice makes it dangerous to be running outside during winters. I have friends who run marathon and one has had knee surgeries and therefore afraid to run in even a little bit of ice.