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.
Another bout of heat for Perth Perth has finally cooled down to about average summer levels over the last few days, and is on track to heat up to a balmy 32 degrees today.
After a slight dip in temperatures yesterday, warmer days are on the way from the Coolangatta area to the Sunshine Coast region.
Temperatures will cool down for much of the week for South Australia, Victoria and New South Wales.