There's not that many places where you end up biking through deep snow, on ice, in -20F for a long part of the season, right? Normally its one of the other (really cold, or ice) - if you have long periods of -20F then you have packed snow on roads, not ice, at least we do back home, and packed snow is fine to go on.
I'm from Sweden, and when I lived in Gothenburg I had no issues biking in -10 - -20C or so (which is what it maxes out at in that area, and even then only for a few weeks at most).
Snow is fine to go on - the worst is like 0C when its been melting and freezing so you get slippery ice, but even then you do fine most of the time as at least the car parts of the roads tend to be maintained with gravel. Assuming you live somewhere that regularly has cold weather your roads are most likely decently graveled too.
I'm from Sweden, and when I lived in Gothenburg I had no issues biking in -10 - -20C or so (which is what it maxes out at in that area, and even then only for a few weeks at most).
Snow is fine to go on - the worst is like 0C when its been melting and freezing so you get slippery ice, but even then you do fine most of the time as at least the car parts of the roads tend to be maintained with gravel. Assuming you live somewhere that regularly has cold weather your roads are most likely decently graveled too.