Agriculture Weather
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.
Southern Oscillation Index
Nino3.4 Index
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Weather News
Soggy week ahead for parts of QLD
13:41 EST
A moisture laden trough will linger across northern and eastern Queensland through the week to come, resulting in large rainfall accumulations.
Super Typhoon Surigae threatening the Philippines with dangerous surf, rain and winds
13:08 EST
Super Typhoon Surigae, as it was named by the JTWC, has strengthened and is looming over the Philippines.
