The short answer is be prepared for anything. Beautiful clear roads, freezing rain, sun, lots of snow, black ice, cloudy skies, bad slippery roads, etc. Very difficult to predict as it can change from day to day and year to year. Best bet is to have supplies in the trunk just in case and adjust your speed and plans based on the weather forecast.
I know this is not very helpful at all, but it is the truth. Anything goes in the winter. One year could be beautiful with little snow and great roads, next could be brutal.
I lived in Dartmouth for five years and commuted to downtown Halifax for work every day. On a great day the commute took only a few mins. On the ansolute worst day it took hours due to bed weather, bridge back ups, etc. there is no real answer to give you. :(