What do you mean the water is too cold, the big white ones love the cold that's why they hang around the South coast most of the time.
From my experience Oct-Dec is the most likely time for them to head up the coast a bit, (usually around Woodies or Mullaloo

) and pick off a few of the smaller, weaker, whale calves as they make there way back down the coast.

Unless of course there is a body dragging kiter on offer instead.