I was in Tassie last Summer and I sailed every day in a spring suit. Water was a nice temperature and most days were actually hot and sunny. Only really got cold at night.
Sure it can get cold at times too, but for some of the best wave sailing you'll find on the planet, dropping a few degrees in water temp is not a major sacrifice.
If you just want fun sailing, blasting around, jumping, etc, then Geraldton is a great spot for that, but if you want epic quality wavesailing then I wouldn't even mention the word 'Geraldton' next to the words 'quality wavesailing'.
Try new things Feerless! you too Radmac!