The round trip cruises from the northeast in winter do encounter cold weather during the first and last day or two of the cruise. It won't be sunning weather on those days, but you can still do some walking around the outdoor decks or reading with a jacket on. The real fun is taking advantage of all the indoor activities on the ship, if the weather is too cold outside.
You'll still have lots of warm weather as the ship gets to its southern ports in Florida and the Caribbean. The cruise won't be ruined at all, just like it wouldn't be ruined if you did indoor things because it was raining outside, or too hot, or whatever.
1) 7 night Carnival Cruise leaving Miami (paying for flights)
2) 9 night Royal Car Cruise leaving New Jersey
Both seem to end up costing me about the same.
So far with my research, Royal seems to be a better cruise (especailly being 9 nights).... the problem is I'm stuck with a 8 hour road trip before and after, and we have to deal with the cold New York weather for a few days of the cruise.
If they end up costing the same, I would fly to Miami and go that route. You can always fly down the day before and fly back the day after your cruise and still have just as long a vacation. With a long, hectic drive in the winter, that would remove some of the relaxation of the cruise. Of course, a couple of extra nights on the ship is worth considering. For me personally, I would prefer to start and end in warm weather.
1992 MV Royal Majesty
1993 MV Royal Majesty
1996 Sun Princess
2007 Liberty of the Seas
2010 Navigator of the Seas
2010 Radiance of the Seas
Would flying to New York/New Jersey put the cruise out of your price range? What about a Royal Caribbean cruise from Florida? Although, if you're going to fly somewhere, it may as well be to Florida if you're worried about the cold northeast weather. Plus, looking forward to an 8-hour drive in each direction is not optimal, especially at the end of the cruise. Having a house on Lake George (NY), I know that driving that time of year can be a pain.
I agree that, if you fly, definitely plan to fly at least a day before the cruise is scheduled to leave, to give yourself some wiggle room in case of bad flying weather or other airline delays.
jharoun- Don't worry in the least about sailing out of the Northeastern US, the ship will be far enough South by the time you are up and about on the first morning the temperature is no longer a problem-the big plus is that you will enjoy those wonderful days at sea to relax and get the true feel of the ship! If a balcony cabin is in your budget-go for it!!