El Niño nears record levels as Pacific waters continue to warm

Models predict further warming of the tropical Pacific through the southern hemisphere spring, probably peaking in late spring or summer (December–February) and continuing into autumn 2027 (March). | Photo Credit: VENKATACHALAPATHY C

El Niño has strengthened to near-record levels, with the Nino3.4 index reaching 2.72°C during the week ending September 27, the second-highest level on record. Models show further warming through spring (October-November), with most models peaking above 3°C.

A positive Indian Ocean Dipole is also likely to develop during the same period, according to the Bureau of Meteorology, Australia’s Southern Hemisphere monitoring report.

Oceanic and atmospheric indices point to a strong El Nino, with further intensification expected through the remainder of spring.

The most recent value of the Nino3.4 index, for the week ending 27 September 2026, is +2.72°C, well above the El Nino threshold (+0.80°C). This is the second-highest value on record in the Bureau’s weekly sea surface temperature (SST) data since 2008, behind +2.76°C for the week ending 22 November 2015.

All models, including the bureau’s, predict further warming of the tropical Pacific through the southern hemisphere spring, probably peaking in late spring or summer (December–February) and continuing into autumn 2027 (March).

Relative-Nino3.4 values are expected to exceed the warmest on record since reliable records began in 1950, with most models forecasting a peak above +3.0°C.

The Indian Ocean Dipole (IOD) is neutral at present; however, the value of the IOD index for the week ending 27 September 2026 is +0.76°C. The index has now been above the positive IOD threshold (+0.4°C) for the third consecutive week. An event is considered established when it is characterised by sustained values above this threshold.

A positive Indian Ocean Dipole (IOD) is likely to develop during the Southern Hemisphere spring and continue into early summer, although model guidance indicates some uncertainty in the strength and duration of the event.

A strong El Nino is also evident in the atmosphere with weakened or reversed trade winds over the western to central tropical Pacific, increased cloudiness over the central to eastern tropical Pacific, and decreased cloudiness over the Maritime Continent, which is the dominant pattern for September, the report said.

The sea surface temperature (SST) analysis for the week ending 26 September 2026 shows warmer-than-average waters around much of Australia’s west, south and southeast, with SSTs up to 3°C above average. SSTs to Australia’s north and northeast have cooled over the past couple of weeks and are now more than 1°C below average in parts.

Global SSTs are still at record levels. SSTs averaged over 60°S to 60°N were at their highest level on record for any month since records began in 1900, 1.04°C above the 1961–1990 average.