Winter influence is what I was referenced.
http://www.bom.gov.au/climate/enso/#tabs=Indian-Ocean
However, four of the five international climate models surveyed by the Bureau indicate the monthly IOD value for November will be within the neutral range, with the remaining model sitting just at the threshold value (i.e. −0.4 °C). A return to neutral weekly IOD values is anticipated in the coming weeks. This is consistent with the typical life cycle of an IOD event, which sees events dissipate in late spring or early summer with the arrival of the Australian monsoon. When the monsoon trough shifts south over the tropical Indian Ocean, it changes wind patterns and prevents an IOD event from forming. This is why IOD events are unable to form (and therefore influence Australian climate) during December to April.