Rahul Somvanshi
El Niño is not coming — it’s already here. And the latest forecasts from both Australia’s Bureau of Meteorology and the World Meteorological Organization suggest it could keep intensifying well into 2027.
What the numbers actually say
The Bureau of Meteorology’s most recent assessment, issued on September 1, put the relative Niño3.4 index at +2.45°C for the week ending August 30. The Niño3.4 index measures sea surface temperature in a key stretch of the central tropical Pacific. Australia’s threshold for declaring El Niño is +0.80°C under its current measurement method.
Models forecast continued warming through spring in the southern hemisphere, with expected values forecast to rise above the highest levels recorded since reliable records began in 1950. That’s not the same as confirming this is the strongest El Niño ever measured — it is a forecast, and forecasts carry uncertainty. But the direction is clear.
The WMO places the likelihood of El Niño persisting through February 2027 at almost 100%, and expects it to strengthen into what it classifies as a very strong event.
What El Niño actually is
El Niño is a natural climate pattern linked to unusually warm ocean temperatures in the central and eastern tropical Pacific. When those waters heat up, they change rainfall and wind patterns across the globe. Historically, strong El Niño events have been linked to drought across parts of Australia, reduced rainfall in some regions, and increased fire risk during the warmer months.
The Bureau is explicit about one thing: a high Niño3.4 reading does not automatically translate into equally strong impacts across Australia. The El Niño signal is one climate driver among several. The WMO’s September 3 update forecasts the development of a positive Indian Ocean Dipole during September–November 2026. A positive IOD on top of El Niño would typically mean a drier and hotter outlook for southern and eastern Australia.
One technical note worth understanding: Australia changed to relative Niño indices in September 2025. That means direct comparisons with older El Niño records need care — the measurement method shifted, and raw numbers from before that date aren’t directly comparable.
Historical context from the Bureau shows that the 2015–16 very strong El Niño was associated with an early fire season, reduced rainfall across northern Australia, prolonged heatwaves, and severe coral bleaching. What the 2026–27 event actually brings will only be clear as it unfolds.
