Hmmm best time of year... I would guess maybe April/May on the assumption that it is usually pretty stable that time of year here, so hopefully it is there too. I would defer to the advice of someone local to Parkes on this matter though... anyone there?
It's definitely pretty warm this time of year! We spent a good while in the air conditioned visitor's centre

. Springtime is often unsettled and stormy/windy here so I guess it is there too. BTW there was maybe a couple of k's of trees torn apart each side of the Newell Highway just near the scope. Probably happened within the last week or so... they put it there for the "stable climatic conditions" I think is the line from "The Dish".
Al.