Was actually hotter here in Adelaide, which really sucked.
I envy your cold snap in Melbourne..
I kept with my suit & tie despite it being absurd to do so in such shitty heat conditions. I actually use my jacket to hold alot of stuff for work so I don't have to carry a man bag. I didn't have an office to take shelter in either...
My only advice - stay hydrated and network rooms (that don't have power failures) are great places to relax in!