Seasonal Climate Outlook

Recent climate

September rainfall was above average for the Central West and Central Wheatbelt forecast districts, below average for South West and South Coastal forecast districts and average elsewhere. September maximum temperatures were average to above average, with below average in land, and minimum temperatures were average to above average. Minimal reports of frost damage.  Rainfall decile map for 1 April to 2 October 2022 shows decile 8-10 rainfall for the majority of the SWLD.

Rainfall decile map for South West Land Division 1 April – 2 October 2022

In September the atmospheric pressure was higher than normal over the SWLD.

Sea surface temperatures have remained warmer than average around much of the Australian coastline, particularly to the north and west. The sea surface temperature outlook for October to December 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 negative Indian Ocean Dipole (IOD) event continues. Models indicate that the negative IOD is likely to persist at least until late spring. A negative IOD typically increases the chance of above average spring rainfall for most of the eastern two thirds of Australia. Past negative IOD events generally increase rainfall in the eastern grainbelt.

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 and is likely to remain generally positive throughout spring into early summer. During the spring months, positive SAM increases the chance of above average rainfall for parts of eastern New South Wales, eastern Victoria, and south-eastern Queensland, but has a drying influence for western Tasmania. SAM has no influence on rainfall in the SLWD in summer. A positive SAM has a drying influence for parts of south-west and south-east Australia at this time of year.  For more information see the Bureau of Meteorology’s Climate Driver Update.

A La Niña is underway in the tropical Pacific. La Niña increases the chance of above average rainfall for northern and eastern Australia during spring and summer, with little influence over the climate of the SWLD. Models indicate the La Niña may peak during spring and return to neutral conditions early in 2023.

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