Hey Sci,
I think you'll find that December is the sultry hot windless season for tropical islands in the southern hemisphere.
you wont get better wind that here in WA. Maybe Margaret River? Then at least you have main break, Augusta, Hamelin Bay, Boat ramps, Boranup etc.
Thats almost cruel leaving WA in peak windy season to visit another place with less wind.

Good luck with it,