Southern Oscillation Index
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.
Now Temperature
At Darwin Ap
20:10 CST
27°C
33°C
Thunderstorms
Weather News
Fire danger about to spike in SE Australia, drop in WA
16:21 EDT
Fire danger is about to spike in South Australia, Tasmania, Victoria and New South Wales and about to drop in Western Australia as an area of hot, dry wind heads east.
Heavy rain and storms hit Queensland
13:09 EDT
Heavy storms are lashing central Queensland, whilst rain and strong winds affect the coast.
Scorching Night for Central NT
13:00 EDT
Parts of Central NT have had their hottest morning in 7 years.
