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.
Authorities are growing frustrated with people continuing to drive across fast-moving creek crossings, as hundreds of millimetres of rain swells river catchments across WA's north.
A national scientific agency says Queensland's UV index so far this summer is higher than in previous years.
Residents have described chaotic scenes in the streets of Mudgee as the town was battered by damaging winds today.