G'day mate, Well i havnt cruised in OZ befor,or anywhere for that mater, but i can tell you that november and decemeber are the hottest months in Australia Temps of 40C plus[110F] and at night its in the 20s [50s] and it can get quit humid. of course this is the extremes its not always that hot but is very commen. It can also be quit stormy at that time of year. But i'm from Queensland so as you go south the climate does change. Melbourne can get 4 seasons in 1 day so have a coat ready just in case. Looking at the tours the cruise is offering if you have time i'd definitly do the blue mountain tour. OH and of course if your a sports fan a day of watching the Aussie cricket team cant be beat.
i hope this is in some way helpful