In Quebec they are now forcing people to have snow tires on their vehicles from November to April. Some (Julian Fantino among them) have voiced support for this idea in Ontario.
Now maybe you could make the case for this in parts of the province, but not in Toronto, it just doesn’t make sense. Even when we had that really nasty snow storm last weekend (and let’s face it, that’s a once-every-five-years storm) the roads were fine in 24 hours. To be sure, snow tires are a wise choice in many circumstances, but given the driving conditions in Toronto (never all that bad) I can’t see making a case for a province-wide law making the things mandatory.