The difference between fair and foul here can mean a temperature change of over 120 degrees between summer and winter and dry roads vs roads packed with several feet of snow and ice.

I have had a dedicated winter bike for as long as I have ridden through our winter... preferred weapon is a bike with a 3 speed internal hub and 26 inch wheels with knobbies and am in the process of building up a new one as my old one was actually too nice to subject to such nasty conditions.