Check out the Graphs section of this site for the wind strength.
www.seabreeze.com.au/graphs/sa.aspI would pack the light wind gear if I was you.
3 / 2 westsuit does the trick almost all year round, except for summer (steaming). The water not VERY cold, but if you are coming from Hong Kong, I would pack one. Although 30 degrees over the weekend, it might not be neccesary for a few days.
Could be a nice seabreeze Sat or Sunday.
(disclaimer - don't take anything I say for gospel as I could be wrong and NEVER EVER trust the weather man!!!)
Hope that helps