A little while ago CheapAir did this study about when air fares are at their best. It was a pretty extensive study as I recall, and they reviewed data from thousands of flights. I went back and found their report and for the Caribbean the optimum time to book a flight with a U.S. airline is exactly 207 days before the day you plan to leave. So, almost seven months. If we took today's date and added 207 days to it then flights to the Caribbean for September 9, 2019 should be at their lowest point today. I'm not sure how they conducted all their research, but it may not hurt to keep those number of days in mind (if possible). In addition, their report said flights to the Caribbean are at their cheapest on Tuesdays and Wednesdays which is something I very much agree with. Of course, all of that research was done prior to Irma so who knows what overall impact that has had.