http://www.bom.gov.au/weather/qld/ is the Gov't weather website for the state I live in. You can access any state's weather from there.
http://www.australiasevereweather.com/ is a site that will give you some hours of interesting info about what to expect.
I live in the tropical North of the country and our winter started today. We only have 2 seasons. They are "The Wet" and "The Dry".
At the moment, clear skies, cold mornings that get down to around 6 degrees Centigrade and max at 22 to 26 degrees during the days with low humidity. This will stay like this until about October.
Further south you will find colder weather, rain, snow and winds.
Summer here ("The Wet") starts around November and goes through till April. Southerners have Spring, Summer and Autumn seasons during that time. What we get is high humidity, cyclones and storms. The sort of weather that rots the fork outa ya jocks while you are wearing them.
Hope you find the links helpfull and when you visit this great country of ours, give a shout and I will buy you a real beer.
Croc.