Trade winds should still be in so could be good. Yorkey's Knob is the best place to go close to cairns. Conditions are 15-25 knots (from what i understand..).
I have been up there on two separate week long trips in the last 2 months and had one decent day (17 knots) amongst it all. It seems to need to be blowing 30-35 knots plus on the open ocean (eg Green Island) before you get something better than sub 15 knots at Yorkeys.
You can go out to Green Island. It seems to be nearly always windy there. I tried this and wouldn't recommend it unless you can get it at high tide. The reef must go out for about 500+ metres - a killer walk over coral if you get caught on low tide (like me !!

)... No good launch areas either. Some of the Kays on the reef looked more promising but could be tricky to get yourself there unless you have lots of $$$. The one i went to with the family (Michelmas) explicitly banned the flying of Kites (bird sanctuary

). Also cost $500 for the 5 of us - ouch ! Would have been nice though! There were some guys flying on one of the Kays on the way out there...
Anyway I think i was a bit unlucky with my Cairns experiences. Yorkey's is a great spot and if you got better luck with conditions would be excellent.
In any case I wouldn't count on kiting every day and i would pack your big one !