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.
Icy and windy weather affecting parts of the NSW central-west and Blue Mountains will continue into tomorrow, although strong coastal winds are easing, the Bureau of Meteorology (BoM) says.
After a slow start to the snow season and a week of small to no surf, an intense cold front has brought some happiness to snowboarders and surfers in Victoria and New South Wales.
Parts of WA have been receiving persistent showers in recent days, propelling some locations well past their monthly average.