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
12:20 CST
30°C
24°C
Possible thunderstorm
Weather News
Heating up across the southeastern capitals
11:19 EDT
A couple of scorchers are on the way for Adelaide, Melbourne, Canberra and Sydney over the next few days.
Darwin not quite that wet (yet)
11:13 EDT
Following a good start to January 2017 rainfall, when 125mm fell during the first 48 hours of the year, conditions have been relatively dry for the Northern Territory capital.
Steamy night in Brisbane
14:29 EDT
In the early hours of the morning, Brisbane had its warmest minimum temperature since at least 1999, when the mercury halted its descent at 28 degrees just after 3am.
