estern Australia is undoubtedly the best place for windsurfing and kitesurfingin Australia during the Australian Summer. The main sailing season runs from November to March, with the months of December and January providing exceptional conditions.
I have been enjoying the summer conditions in WA for just on 30 years. Arguably global warming has reduced the wind strength a little over this time, but the prevalence of larger volume wave boards still makes the sailing exceptional and regular. Also, with the advent of kitesurfing, a keen water sports person can get 5 good days sailing per week on average.
The main recognised sailing areas are Esperance, Margaret River, Perth, Lancelin, Geraldton and Gnaraloo. This site describes the conditions and resources in these areas (some of the descriptions are under construction).
Western Australia is also a very interesting area for the tourist. It is an extremely large state, with a large coastline, and a hot and arid interior. An excellent reference for a description of the area is the Welcome to Western Australia web site.
Auinfo.com also has useful information about the area, including descriptions of some of the main towns, as well as accommodation details that can be useful.