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.

The current La Nina event continues to strengthen, with some tipping it could reach 2010 levels, but only briefly and with less flooding.

The type of rain-bringing weather event is more difficult to accurately predict in terms of the location of rainfall than other systems.

There is an average to slightly above-average number of tropical cyclones this season.

There has been a heavy band of rain pass through Victoria and South Australia delivering the heaviest October rain in 15 years for some.

The Bureau of Meteorology has confirmed Australia will experience a La Nina weather event this spring and summer.

American meteorologists have officially called a La Nina event in the Pacific Ocean but the BOM is holding off on a similar call - for now.