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.
Much of southeastern Australia is experiencing its sunniest week since spring and skies have been staying clear at night, effectively giving planet gazers a fine-tuned view of a rare feature.
Australia's western capital equalled its record of four consecutive days over 40 degrees yesterday, and some of that heat is returning.
The tiny community of Palmers Island in northern New South Wales has rallied around two residents left homeless after a super cell storm.