I agree Spring can be very changeable in Vic and southern NSW, also can be windy. With this knowledge we set off for the Great Ocean Road in early March, had a couple of beautiful days then got caught be a scary storm and the cold wind and rain continued for at least a week. We took refuge in a nice little place called Nelson, out of the wind at last.
Theres really no guarantees with weather nowadays, we have to be like boy scouts and always be prepared!