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Agriculture Victoria

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Climate Drivers

Article printed April 23, 2024. For the latest version, please go to: https://www.feedinglivestock.vic.gov.au/climate-drivers/

Four key climate drivers have major effects on our wetter and drier seasons.

ENSO (El-Nino/Southern Oscillation) – refers to sources of rain-bearing moisture that comes from the tropical Pacific Ocean.

IOD (Indian Ocean Dipole) – refers to changes in ocean temperatures off Africa and Indonesia that affect moisture sources to our north-west and alters the position of fronts and lows across south-east Australia.

SAM (Southern Annular Mode) – refers to belts of westerly winds that circulate around the southern ocean and can influence the strength of frontal activity and rain triggers that get to Victoria.

STR (Subtropical Ridge) – is a natural high pressure belt that sits across southern parts of Australia and can influence the location and strength of high pressure systems. The STR can be affected by ENSO, IOD and SAM.

Need a more detailed explanation of climate drivers?

Chapter 1: Sheep Drought Book (PDF Document) →

Chapter 1: Beef Drought Book →

Further information?

  • Subscribe to ‘The Break’ – Agriculture Victoria’s free monthly email update.
  • Watch the Very Fast Break on YouTube – produced by Agriculture Victoria.
  • Watch Bureau of Meteorology seasonal video snapshots for rainfall and temperatures.
  • Download the CliMate app to look up your nearest long-term rainfall station data and then ask questions like “How often we do we get autumn breaks with 50mm over 2 weeks in March-May?”