The heatwave in southern states has been doused by rain as temperatures rise to near record levels in Sydney today.
The official onset of the monsoon in Darwin occurred in the week before Christmas and about a month earlier than last year.
The La Nina event had failed to get the summer wet season started in the tropics until it got help from the Madden Julian Oscillation.
UPDATED: Tornado associated with a vigorous cold front has caused significant damage in the Victorian town of Horsham.
It may not feel like with the heatwave on the way for much of the country over the next week but the La Nina weather event is strengthening.