Try and keep the bike indoors overnight at least, and if possible during the day - that will stop any deep freezes of any cables/components, but if the bike is in a shed/garage, then in a bike shed at work, things will freeze up fast.
I've had a freehub freeze on the MTB meaning having to abort a ride, but that was 2 years ago - during last winter/this winter, when the 'geared' bike (e.g. the MTB with spikes) was required, it comes indoors. The fixed can stay in the garage (now't to freeze)....
With this, haven't had any issues, even with the mechs/gears covered in thick ice/snow from off road riding.
Hope that helps.