:shock: I'm amazed by Algonam weather in Canada!!. We had rain, sleet, snow and hail yesterday and 22 F this am.
I've done both wrapping and not, and had bees survive and thrive come Spring (even left a SBB wide open one winter and those bees became an awesome and productive colony, that was 'dumb' luck'), but I am convinced wrapping w/ tar paper reduces "wind" infiltration (a killer when temps, not just wind chill, can get to 35 below zero) and heats the hive during sunny periods as explained by bluebee.
As for moisture issues, I use notched inner cover 'Top' entrances w/ a 'vent box above that' I fill w/ dry sugar and place 2" ridged insulation on top, under telescopic cover. I wrap the hole thing with tar paper, vent box and all, leaving only the top (opening cut down to 1/2" max) and bottom (1/4" max) entries open.
Despite warnings (mice) I place hay all around my hives about half way up and when snow comes I'll cover w/ that as well. By Spring (if there's been a lot of snow) a cavity has formed around the 'survivor' hives but still provides protection from late Spring storms. I've taken off the tar paper later and later each year. This next season I'm waiting until the dandelions are in full bloom, around mid May. Better late than early, at least up here.