WINDY MILLER said...
wind / air chill is going to be the biggest factor....
Only if you fall in...

...I've paddled almost daily through the last couple of Winters here in Melbourne and I find that you get way too hot in a wetsuit.
I bought some waterskiing wetsuit shorts and wore them under my boardies..and a wetsuit vest...and then a T shirt or a windcheater over the top.
My crocs on my feet were enough to keep my feet warm..and my alloy paddle was a bit cold on the hands at first..but it soon warmed up.
I bought a wetsuit material long sleeve top and wore it once or twice..Most of the time just the vest was enough.
Note...all this paddling was on flat water and the odd day in glassy tiny waves were there was no risk of falling in..but still did sometimes..and froze..

Real surf sup'ing down here would require a full wetsuit..I reckon a long leg and short sleeves would be the go.
Paddling really keeps you warm..much warmer than when you're in the water..imo..but then it also depends on the wind..if any..

DJ