on average Ft. Lauderdale can be a bit on the cool side at night in late February early march. Warm enough for shorts & swimming in the day time(of course we are from New England) but we needed a light jacket at night. The further you get into the Caribbean the warmer it becomes. Our first at sea day was a bit on cool side, with the ocean breezes but we still hung out at the pool. St.Maarten was beautiful, warm and sunny.