Glenn,
Don't know what "zone". I'm in Melbourne Australia (State of Victoria) and these are the state averages to give you a rough idea:
"Victoria's seasonal climate:
Victoria experiences warm to hot summers, mild autumns, cool to cold winters and cool springs. The climate varies across the state, with the north experiencing much drier and warmer weather than the south."
Summer: December to February
Temperatures: from 21°C to 34°C, average 28°C
Autumn: March to May
Temperatures: from 11°C to 19°C, average 17°C
Winter: June to August
Temperatures: from -1°C to 12°C, average 8°C
Spring: September to November
Temperatures: from 10°C to 20°C, average 17°C