I commute through the winter in conditions similar to what @
Ged117 describes in Ottawa, but not quite as cold typically here in Boston. The streets are similarly deeply brined before and after any idea of snow, and that's really tough on any bike. I killed one Sturmey-Archer two-speed kickback hub commuting one winter, and have actually mostly used derailleur-equipped bikes for the last few years. I don't expect the components to last more than one winter, but they have made it through without undue difficulty. I might have to build a winter-specific IGH bike just for the heck of it.