I have created this basic map of Australia to show the hardiness of Dragon fruit in Australia.  With this please remember Micro climates can exist and the varieties you choose will also vary with cold or heat tolerance. 

Dragon fruit (Hylocereus spp.) is a tropical fruit that thrives in warm climates. T

he optimum temperature for growing dragon fruit is between 18°C and 35°C. However, the plant can tolerate temperatures outside this range to some extent.

Here's a breakdown of temperature requirements for different growth stages:

1. Dragon fruit seed germination: Dragon fruit seeds germinate best at temperatures around 24°C to 29°C.

2. Dragon fruit vegetative growth: For optimal vegetative growth, temperatures between 27°C to 35°C.

3. Dragon fruit flowering and fruiting: Dragon fruit plants tend to flower and set fruit when the temperature stays between 18°C to 32°c. Temperatures above 35°C can inhibit flower formation and fruit set.

4. Dormancy: Dragon fruit plants may experience a dormant period when temperatures drop below 15°c. During this time, the plant growth slows down.

5. Shorter dragon fruit growing season:The colder your climate and the shorter the day light hours the shorter your dragon fruit season will be. 

It's important to note that while dragon fruit plants can tolerate some temperature variations, prolonged exposure to temperatures outside the optimal range may result in reduced growth, flowering, and fruiting. In colder climates, it's advisable to grow dragon fruit in containers or greenhouses where you can control the temperature better and protect the plants during colder seasons.

Additionally, proper watering, well-draining soil, and sufficient sunlight are also crucial factors for successful dragon fruit cultivation.