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.
Snow continues to affect 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.
Snowfalls in southern Tasmania have trapped a number of cars on a highway south of Hobart.
Papua New Guinea's prime minister Peter O'Neill says he may review a recent ban on importing Australian fruit and vegetables into the country.