Thank you so much! Habitat photos and information are always useful!
Here is midsummer weather at Norah Head:
Norah Head, NSW - December 2017 - Daily Weather Observations
and midwinter
Norah Head, NSW - July 2018 - Daily Weather Observations
Remember
10C = 50 F
20C = 68 F
30C = 86 F
40C = 104 F
It's very much like Honolulu, Hawaii. Casuarina trees grow right on the beach throughout the tropics of the world due to their floating seed capsules.
Sarah Jean, other Dockrillias grow in very different environments than this. Some species get much less sun. Some have distinct seasonal humidity and/or rain variation. It is important to look up the conditions for individual species.
I have linguiforme, prenticei and toressae. All do well with bright shade, moderate humidity and frequent watering through the year. I've been told higher humidity is fine, but they're not getting that here.
They would do great for you outside in bright shade under a tree, so long as it's above freezing.