You can kite all year round here mate.Wind is less consistant through the winter ,but he waves are bigger.
July ,August and early September are good through the winter and coming out of winter for waves and wind.Perth has long stretchs of beaches with crappy waves in the summer,but down the south west has nicly sized waves.This a 3 to 4 hour drive .The wind is ver consistent in the summer
Lancelin is only an hour north of perths suburbs and has small to medium size waves and downwinder locations
Mandurah to Geralton has good down winder beach break locations scattered all up the coast where as down south at the famous location of Margeret river and surrounds are more point breaks and big powerfull swells.
There are some fun little waves an hour north and south of perths CBD