It's like your winters, its hit or miss for a snowstorm.
You won't have any issues going out of NYC, we haven't had a direct hit with a hurricane since the 80's (yes, long overdue!). The storms basically bounce off North Carolina (or go through inward to the other states) and go off into the North Atlantic & spin out to sea towards England. It loses strength since the waters here above North Carolina are so cold & fizzle out.
That being said, the cruise line could do one of two things; change your itinerary to visit the towns here in the Northeast into Canada (think Nova Scotia, Maine, Boston, etc) or maybe head towards Bermuda.
It's like anything during hurricane season. You know there's a chance, but you take the crap shot it won't happen.
New York is tough to cruise from - there's nothing really here on the East Coast for choices for cruises should they have to change plans.
Serenade of the Seas - '05
Sovereign of the Seas - '07
Well, we thought we were safe sailing out of Miami on October 21, 2005 but we sailed right into Hurricane Wilma. We had a great time even tho we were rockin' and rollin' pretty good. My grandson still talks about the "crazy boat" cruise, ha!
I agree with Cassandra. GO FOR IT! The chances of having a hurricane interfere with your cruise are small, and even if it does, the worst that could happen is more sea days, or ports other than those you had intended to stop at. I live here in Florida, and book at least two, sometimes three cruises every year during hurricane season, and have yet to miss one. Yep, I've gone to other ports, but I cruise for the ship anyway, not necessarily for the ports. Book it, and enjoy.