Agriculture Weather


Southern Oscillation Index

  • location
  • Aus

The Southern Oscillation Index (SOI) is calculated from the monthly or seasonal fluctuations in the air pressure difference between Tahiti and Darwin.

A strongly and consistently positive SOI pattern (e.g. consistently above about +6 over a two month period) is related to a high probability of above the long-term average (median) rainfall for many areas of Australia, especially areas of eastern Australia (including northern Tasmania) - La Niña.

Conversely, a 'deep' and consistently negative SOI pattern (less than about minus 6 over a two month period, with little change over that period) is related to a high probability of below median rainfall for many areas of Australia at certain times of the year - El Niño.

However, it is important to remember that the pattern of relationship between SOI and rainfall (and temperature) can vary depending on the particular season and region. Additionally, the change in SOI over a specified period can be as important in understanding relationships between SOI and rainfall as is the absolute value in SOI.

Southern Oscillation Index

SOI

Nino3.4 Index

Nino3.4
Display Your Local Weather

Weather News

Queensland storms bring hail and high winds, causing power outages

09:13 EDT

The clean-up is underway after severe thunderstorms left a trail of damage but little precious rain in parts of South-East Queensland and the Darling Downs.

Government offers one-off payment for farmers coming off Farm Household Allowance

17:29 EDT

Farmers coming off welfare will be entitled to a new, one-off payment of $13,000 for families and $7,500 for individuals.

Severe storms forming over NSW and Queensland

13:47 EDT

Potentially severe thunderstorms are developing in parts of NSW and Queensland, with warnings in place for parts of both states.