Most guides split Australia into regions to help you decide what to plant when. This is confusing because each guide has us ina different region. Add to that the seed packets and the labels on purchased seedleings also have theri own opinion.

I think that a combination of what suits me out of what they all say is the best way to go. It is quite hot and quite frosty out here, but the vegetable garden doesn’t get most frosts – I have tomatoes and eggplants still flowering and producing fruit and it is mid May.

Eden Seeds classes us as Mild
: http://www.edenseeds.com.au/content/planting.asp
Gardening Australia  has 5 zones and Sydney is in the Temperate Zone
http://www.abc.net.au/gardening/vegieguide/
Gardenate.com classes us as Sub tropical
Warm humid summer (average January maximum temperature < 30 degrees C). Mild dry winter. Includes the eastern seaboard from Brisbane south through Coffs Harbour to Sydney. Coastal WA from approx Geraldton to Canarvon
 
http://www.gardenate.com/?zone=3[/box]
 
And Mediterrranean also seems to fit