The NINO3.4 index is one of several El Niño/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 Niño 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 Niño or La Niña event is identified if the 5-month running-average of the NINO3.4 index exceeds +0.4°C for El Niño or -0.4°C for La Niña for at least 6 consecutive months.
A very cold airmass coupled with vigorous a low pressure system caused snow to fall to low levels in Tasmania last night and into this morning, leading to road delays and closures.
Shoalhaven oyster farmers face hundreds of thousands of dollars in losses as floods wash away salinity
Oyster farms flooded in this week's downpour at Greenwell Point on the New South Wales south coast could lose hundreds of thousands of dollars' worth of oysters.
Snow has affected some roads in Tasmania's south, prompting police to warn drivers to use extreme caution after a number of motorists were left stranded on Friday night.