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.
A Brisbane storm chaser is finding new ways to keep residents informed about approaching wild weather, as south east Queensland's storm season ramps up.
The clean-up is continuing after a severe storm hit the New South Wales North Coast on Sunday afternoon leaving thousands without power and displacing some patients at Lismore Base Hospital.
It's beginning to feel a lot like Christmas, and now snow is expected again in Tasmania on Tuesday evening.