Off to Oz in five weeks; haven't flown there but apparently the cloudbase is off the beserk scale, oxygen required, that sort of thing.
Where in OZ?
I flew in OZ in 2012 (in winter - mid-year) and again in 2013 (in summer - around Christmas). Winter was very much like the British summer; but summer was quite different where cloud base was 12-15 thousand feet and you could "in theory" thermal all the way up. However, where I was flying the transponder level was 10 thousand so you kept under that.
Flying into a 12+ thermal was like being hit by a train and then staying in it was like being in a washing machine. I also remember forgoing stronger thermals in the blue to take weaker thermals under clouds just to hide from the sun. One vivid memory of flying in OZ during summer was 39 degrees on the ground and still 30 degrees at 2-3 thousand feet - it was a relief to climb above that into cooler air as the cockpit was worse than a greenhouse - coming back down below 2-3 thousand was torture.
I've turned up at the little OZ club I was flying at more than once with perfect skies with Cu popping everywhere at 5 thousand plus and been told they weren't opening the hangar doors as the day wasn't good enough; so they were going to mow the grass instead. But like everything in gliding - the weather may be against you. I've traveled half-way around the world to fly - and the airfield was 10 feet under water only a few weeks after being evacuated because of being threatened by a bush fire.