An unusual weather pattern is in place over Australia.
There is a low near Tasmania, and a high south of Perth. Remember that in the southern hemisphere, winds go clockwise around a low and anticlockwise around a high. As a result, a big pool of very cold moist air is being swept up from the Southern Ocean and blasted over Southern Australia.
So we're having a top of 11 degrees centigrade, showers, small hail, and a chance of snow in the Mt Lofty ranges near the city. Although right now it is sunny outside.