Cold Zones (CZ)

The Cold Zone of an area is determined by the absolute minimum temperature that could occur in a given area. For example, if a plant has a CZ rating of 9a it can survive temperatures as low as -7°C, whereas a plant with a CZ rating of 10 will likely be killed by a frost.

Cold zone examples within major areas:

  • Temperate (CZ 8, 9a, 9b) include Canberra, Kalgoorlie, Bendigo, Ballarat, Albury, Mildura, Griffith, Wagga Wagga, Bathurst, Orange, Dubbo, Adelaide Hills, Riverland, Riverina and Sunraysia
  • Sub-tropical (CZ 10) include Brisbane, Sydney, Melbourne, Adelaide, Albany, Bunbury, Mornington Peninsula, Geelong, Bega, Coffs Harbour, Byron Bay and the Sunshine Coast
  • Tropical (CZ 11 & 12) include Darwin, Cairns, Townsville, Broome, Mt Isa and Perth.
10a
10b
11a
11b
12a
12b
13a
7b
8a
8b
9a
9b