August saw a weak burst of tropical influence that left north of Port Augusta wetter than average. Further south, rainfall for the month was nearer average, and tended drier in the southeast. This pattern was typical of late winter, and the weak climate borderline La Niña and negative Indian Ocean Dipole influences currently at play. These influences produce moisture from warmer seas around northern Australia, but bursts of tropical activity that might push this moisture down south for rain have been weak.

The shift to La Niña has strengthened from late August with the SOI just gone above +7, the La Niña threshold. The Southern Annular Mode (SAM) has also headed positive which tends to be the case in La Niña events. Positive SAM sees cold fronts staying further south – hence the drier south-east of SA and western Tasmania.
As weather systems shift south, as they do every spring this will allow the tropics to have more influence- when there is a burst of tropical activity to work off the warmer seas around northern Australia.
Looks like this will be the case from the last week of September onwards, with a weak burst of MJO activity in phase 4/5 in the outlooks.
The various outlook modelling has the IOD back to neutral by December as is typical for the IOD, and La Niña conditions weakening from January on, also typical as December tends to be the month impacted most strongly by La Niña when it is happening.
So what conditions can we expect? Wetter end to September with rainfall near average for Adelaide. Temperatures slightly above average, particularly through the first half of the month.
For October and November, wetter than average conditions from the combination of the IOD and La Niña, and near average temperatures.
The next few months will likely see higher risk of rot and fungal issues to keep an eye on for growers, lower water use than typical and lower heatwave risk. And the risk of rain through harvest to negotiate.
Summer overall would be expected to be wetter than average, with milder temperatures for that time of the year and lower heatwave risk from cloudier conditions. That looks to be the case for December particularly.