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 old saying is that you know it is hot when birds start falling out of the sky.
El Nino reared its head this spring, delivering a scorcher to New South Wales.
Record prices, new export markets and rain â?? from the Tanami Desert to the Roper Gulf, and Daly Waters to the MacDonnell Ranges, four Northern Territory pastoralists have shared the ups and downs of 2015 with ABC Rural.