A positive Indian Ocean Dipole (IOD) event occurred during spring 2012. Even though sea surface temperatures (SSTs) southwest of Indonesia were warmer than average, SST anomalies off the Horn of Africa were even greater. The SST deciles map below illustrates the east-west difference in SSTs at the time.
Spring rainfall over southeastern Australia was mostly below average. The spring 2012 rainfall deciles map shows South Australia recorded its 5th driest spring on record (there is less than 1 mm difference between 3rd and 5th ranked driest springs for South Australia).
The spring 2012 maximum temperature deciles map shows most of Australia recorded daytime temperatures in the top 10% of historic records for spring. Spring 2012 was Australia's 3rd warmest on record at the time still ranks as the 6th warmest today.
Typical of positive IOD events, the strongest minimum temperature anomalies were over southern Western Australia. Overnight temperatures in southern Western Australia were mostly in the top 10% of historic records. Combined with the warmer than average daytimes, spring 2012 was Western Australia's 5th warmest spring on record for mean temperatures (the average of the maximum and minimum temperatures).
