Look at a map. Where do you consider there's warm waters?
NYC to Norfolk is 369 miles
At 20 kts = 16 hours, At 24 kts = 13.33 hours
NYC to Wilmington is 629 miles
At 20 kts = 27.33 hours, At 24 kts = 22.8 hours
NYC to Charleston is 760 miles
At 20 kts = 33 hours, At 24 kts = 27.5 hours
NYC to Savanaha is 813 miles
At 20 kts = 35.33 hours, At 24 kts = 29.5 hours
NYC to Jacksonville is 947 miles
At 20 kts = 41.17 hours, At 24 kts = 34.33 hours
NYC to Miami is 1309 miles.
At 20 kts = 57 hours, At 24 kts = 47.5 hours
All NCL ships departing from New York are capable of speeds of at least 20 knots, the Crown being the slowest, which is equivalent to 23 miles per hour. The Spirit and Dawn maximum speed is 24 knots which is equivalent to 27.6 miles per hour.
Just add these elapse times to your departure time from New York City, and you'll have a fairly good idea.
I hope this helps!