It's never as cold at Maldon as at Maine. It may be a bit wet but a brolly is probably as good as anything unless the breeze is up. Ordinary bushwalking gear (decent jumper, or sweater for US citizens) and/or a Lands End "Squall" would be sufficient most of the time. If you had a goretex jacket like LL Bean's "Maine Warden" that would be overkill but waterproof. Joggers would be perfectly sufficient unless you wanted to dance; leather soles are the go, as you'd know. Cotton drill work trousers are warm enough usually.

Spring in Victoria can be sunny, blowy, wet, and/or a bit cool but rarely "cold" in the way you get in Maine. You could look up the Bureau Of Meteorology site for more details. Just remember that our "Low pressure" systems have their winds clockwise around them rather than anticlockwise.

Cheers, Rowan