Cairns is the best option. Yes, it is a 3hr flight (direct), but weather wise it will be perfect - little rain, mid to high 20s (celcius) and at night you might need a jacket.
http://www.bom.gov.au/climate/dwo/20...4.201505.shtml
Check out Palm Cove (20mins north of Cairns) or Port Douglas (45mins north of Cairns).