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.
Bedgerabong in the central west of New South Wales has been isolated by flood waters.
Farmers across Western Australia's grain growing regions have been dealt a bitter blow, with their hopes of record crops dashed by frost just weeks before harvest.
Wet weather "on par" with a system that caused widespread flooding across Adelaide earlier this month has been forecast to hit the Mount Lofty Ranges on Wednesday and Thursday.