Could be anything, bring some bump and jumps stuff for the westerlies at dorans, but maybe some waves at Carlton.
Expect anything from 5 to 45 knots but probably mostly around 15-25.
The temperature can get down about bit then
Water temp in the low TEENS or maybe single digits depending where you sail, so bring a good wetty and booties. 
And there could be nothing!
we are going into "the could blow for 3 days a week, or might shut right down till spring"
best check the weather patterns closer to when you come down here.
How's this:
Wetsuit: A 3/2 steamer, 2mm hooded vest, 3mm dive boots (that's if they'll even fit in the straps - jeez) ....will I survive? I guess the fact that you're out of the water (mostly) with a high heart rate would make it a lot warmer; I've been diving and snorkelling in Tas and I know how cold it is once you're fully immersed.
I may even chicken out and not sail at all this trip...maybe wait til I'm back in the summer!
It's not that cold, especially not in May. It's more the wind chill that gets to your hands on days under 14 degrees.
