Fairfax Media Network

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 Niņa.

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 Niņo.

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

Myer redevelopment flooding: Safety concerns hamper efforts to repair Hobart Rivulet breach

16:05 EST

Safety concerns have held up remediation works at the Myer store redevelopment in the Hobart CBD, which has been flooded after a rivulet wall collapsed.

Squally Sunday for southwestern WA

15:33 EST

Conditions are set to take a turn for the worse over the weekend as a cold front bears down on southwestern WA.

Winton dinosaur museum open for business after two-week closure due to floodwaters

14:43 EST

Visitors can again make it through to the Australian Age of Dinosaurs Museum in outback Queensland after floodwaters forced the iconic attraction to shut up shop for two weeks.