Welcome - winters here can be unpredictable. Two years ago we were hammered by some of the worst snowstorms ever seen in this area, but last year I don't think we had any snowfall at all.
You can probably get by no problem running all seasons if you're looking to save some on cost. I myself have a dedicated winter set I run between Dec-Feb just to be safe.
2010 335i xdrive M sport - Sold