I'm sure there isn't a contractor out there that's going to turn down a job because it's too cold out. It may get postponed a bit due to snow, ice, extreme cold, etc., but under normal cold, winter conditions, a contractor is probably just gonna tell the homeowner that the only 'real' risk to roofing in the cold is that the shingles won't properly seal AND, that leaves the roof 'exposed' to shingles coming off in the wind. Not to mention that because of the shingles not sealing properly in cold, water/ice may work its way up under the shingles which eventually leads to ice damming and the like. (If water gets to the roofing nails, it may work its way 'down' the nail, into the attic, or roof space, and eventually start a leak inside the house.) NOW, this is a house I just got finished talking about. My original question regarded a shed and wondering if I should, or should not, tar paper the sheathing even though the roof is gonna be covered with blue plastic and NOT shingled until Spring.
So, to answer YOUR question, I would hold off shingling a house roof until Spring if at all possible. Your second option would be to patch. A third option is to have the roof done anyway on a relatively warm day and take your chances with the wind blowing off your shingles because they aren't sealing properly. And lastly, I've heard of people putting up shingles in the winter and using a hairdryer to 'soften' up the sealing strip so the shingles seal (Not me)!!!
Back to the shed ... knowing that you have sheathing installed and you're gonna cover the roof with blue plastic AND you're not going to shingle until Spring, would you tarpaper the roof now or wait until Spring? Your comments, please, on that.