The official tourist season for Queensland is from April to November – the winter months are usually the busiest time when all the Aussies from the southern states come up to escape the cold. Also to note that during the high season from June to September, and along with the Easter and Christmas periods, everything is booked out. Weather-wise there is no specific climate change between winter and summer because Queensland is a tropical state so you should look at the weather in terms of wet and dry seasons. April to December is considered to be the dry season but the heat can be oppressive. The wet season (usually January and February) is more prevalent in the outback and northern parts of Queensland though they can affect the southern areas, including Brisbane. So the best time to go is from June to October when the extreme heat and humidity of the summer is replaced with warm days and cool nights.