i’ve found one of the cheapest times is from mid to end of January - For package all incl from Toronto, this year prices started to drop for jan departures about 5th jan when we booked last Nov; right now it looks like prices are dropping for Jan 14th and thereafter departures in jan.2008
Another time of low AI packages is October.
Risks of course for both - Jan this year was nice - but some years cool. October sometimes still has storms (this year Noel caused bad weatehr in south) but only some strong winds and red flags on beaches jus east of Havana where I was.