Heat Zones (HZ)

The Heat Zone of an area is determined by the average number of days above 30°C the zone will experience in a year. Some plants will not perform in extreme prolonged heat, especially in the tropics where the lack of chill prevents fruiting and flowering.

Excessive heat is the major cause of plant failure in Australia - some plants suffer physiological damage when the temperature rises above 30°C. The heat zone map indicates how many days over 30°C each of the 14 Heat Zones experiences, and helps you choose plants that suit your climate.