Rainfall patterns are different in the south of Australia to the north, amelie. In the north the wet season is around January-March, this year extended into early April. In the south it tends to rain more in winter than in the north. I'd also vote for June over August, Sydney and Gold Coast can be affected by cold westerly winds in August.

Queensland has a vast variety of temperature, elnap29, where were you? For example one of the coldest towns is Stanthorpe, down on the Granite Belt, where Sept averages are min 9C to max 19.5C, whereas Cloncurry for the same month is min 16.7C to max 33.4C.

For the most part, we were within a 2 - 3 hour radious of Mackay. We visited Sydney on the way in and on the way out.