This was a concern of mine as well, Paul. I booked a cruise on the Breakaway leaving on October 6th. Hopefully it won't be too chilly for long. If it is, then I guess it'll be a lesson learned for me. Once we get through the first cold season, I think we'll have a better idea if cruising out of NYC year round will work for the Breakaway.
I saw the Breakaway has cruises to nowhere in January, which I find rather odd. I don't think they would have any time to spend outside during those short cruises.
It'll be interesting to see how all of this pans out.