Most of the general trends you should expect:
Winter (Jan - early March) = Fairly cheap
Spring (mid-March - May) = More expensive; esp. for Spring Break
Summer (June - mid August) = Most expensive
Late Summer/Fall (mid-August - early November) = Cheapest time to go and I'd imagine the weather is beautiful too (except for hurricanes.)
Christmas/New Years = Very expensive
Obviously, there are exceptions to that given holidays, etc. But it's generally how it goes with cruises and just about any beach/tourist area in Florida.
Although our anniversary is in late September and it would be an ideal time to go financially, my wife is a teacher and would just be getting back in the groove only to take off and go on a long vacation (burning a lot of vacation days early in the school year in the process.) We really wanted to go in late spring, when it's warm, but not smoldering hot. But the closer you get to summer, the more expensive it GENERALLY gets.
However, there's about a three week span between late April and mid-May where tourist traffic drops off. The main reason revolves around schools. Most schools go on Spring Break somewhere between late March and mid-April. After the Spring Break rush dies down, there's a lull between that time and the rush when the first schools get out again for the summer (generally in mid-May and picking up quickly in June.) This lull is an ideal time to book a vacation as the weather is beautiful, but things aren't nearly as crowded as they were a month before (or will be a month later.) MOST places tend to have cheaper rates at this time too. And when I was looking for our
Disney cruise this was no exception. There was a cruise in mid-May that had the cheapest rate available from any cruise from April-August. Unfortunately, my wife can't take off at that time.

But we still got an early booking discount for one a couple weeks later. In fact, two days after we booked our vacation the price shot up $300 a ticket. That $600 will be going to some other toys for myself now
