This is an important point. If you are serious about commuting in winter, buy 2 tires and use them all winter. Last time I took my summer bike out in the winter, it was a gorgeous day in the 50s and I managed to locate the one section of ice on the road....

That's why you ride with studs. 95% of the trip will probably be bare pavement. It's the 5% you still need to navigate.