Robertson does not have an automatic weather recording station (official one, anyway). So the closest is Moss Vale.
I know I was trying to do some important writing last night, but I could not keep going, as I was so cold.
Anyway, this morning I checked the Moss Vale Weather site, and it said -5.8* Celsius. That is about 25 Km west,a nd admiotedly is more likely to be colder than Robbo. But because our climate is so moist, we get really dense white frosts, once the temperature drops low enough.
I have a sloping site, below a line of tall hedging trees, so, in winter it is in total shade all day.
Late in the afternoon (4:40PM) there was still an unmelted frost on a sand pile. There was still a "permafrost" (little crystals of ice underneath the soil, lifting up small pebbles and rocks).
I forgot to look at the Tree Dahlia, but I am sure it will have been knocked back to the ground (as it has been in previous years). I shall check tomorrow.