Seasonal Climate Outlook

Recent climate

May rainfall was mostly average for the SWLD. May maximum temperatures were average to above average, with minimum temperatures average.  Rainfall decile map for 1 April to 5 June 2022 shows decile 8-10 rainfall for South East Coastal and parts of the Great Southern, Central Wheatbelt and Central West forecast districts.

Rainfall decile map for South West Land Division 1 April - 5 June indicating 8-10 decile rainfall for South East Coastal district, generally decile 4-7 elsewhere.
Rainfall decile map for South West Land Division 1 April-5 June

In May the atmospheric pressure was below normal over the SWLD.

In May, sea surface temperatures were warmer than average around tropical Australia. The July to September, sea surface temperature outlook by the Bureau of Meteorology indicates SSTs are likely to remain warmer than normal around Western Australia and the north and south-east of Australia.

The Indian Ocean Dipole (IOD) is neutral. Models are indicating the development of a negative IOD in July and persisting until at least October at this stage. Past negative IOD events generally increase rainfall in the eastern grainbelt. Outlook accuracy begins to significantly improve during June.

The Southern Annular Mode (SAM), also known as the Antarctic Oscillation (AAO), describes the north–south movement of the westerly wind belt that circles Antarctica, dominating the middle to higher latitudes of the southern hemisphere. SAM is currently positive (but went negative in late May) which may suppress the activity of cold fronts in the Southern Ocean. SAM is forecast to be negative by 12 June and then return to neutral until the beginning of July. For more information see the Bureau of Meteorology’s Climate Driver Update.

The La Niña remains active in the tropical Pacific Ocean. Majority of models indicate a return to neutral ENSO conditions by July.

The table below gives a summary of past month and three-month South West Land Division (SWLD) climate conditions, and can indicate what is likely to occur in the near future if climate conditions follow the current pattern.

Climate Indicator Past month Past 3 months
SWLD Rainfall Average Average to above average
SWLD Mean Temperature Average to above average Average to above average
SWLD atmospheric pressure Lower than normal Normal
Indian Ocean Sea surface temperature Warmer Warmer
El Niño/Southern Oscillation (ENSO) La Niña La Niña
Indian Ocean Dipole (IOD) Neutral Neutral
Southern Annular Mode (SAM) Negative Positive