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.
A tropical low off north Queensland has a high chance of developing into a cyclone and making landfall by early next week, the Bureau of Meteorology (BOM) says.
Queensland may see its first tropical cyclone in two years in coming days, although the situation is still hard to call.
It runs one of the most-viewed websites in Australia and broadcasts its weather forecasts and warnings around the country each day.