The NINO3.4 index is one of several El Niņo/Southern Oscillation (ENSO) indicators based on sea surface temperatures.
NINO3.4 is the average sea surface temperature anomaly in the region bounded by 5°N to 5°S, from 170°W to 120°W. This region has large variability on El Niņo time scales, and is close to the region where changes in local sea-surface temperature are important for shifting the large region of rainfall typically located in the far western Pacific.
An El Niņo or La Niņa event is identified if the 5-month running-average of the NINO3.4 index exceeds +0.4°C for El Niņo or -0.4°C for La Niņa for at least 6 consecutive months.
The final rainband of the season is sweeping across South Australia today, but the heaviest rain is going to fall where it shouldn't.
Farmer confidence in Tasmania has dropped to a three-year low off the back of major flooding in the state's north and retrospective cuts to milk prices.
Bureau of Meteorology (BoM) staff from across the country have begun a fortnight of industrial action following failed negotiations over pay and conditions.