The El Niño–Southern Oscillation (ENSO) is showing clear signs of shifting towards El Niño, with rapid warming in the tropical Pacific and supportive sub-surface conditions, though it is neutral currently.
All climate models indicate sea surface temperatures could cross El Niño thresholds by June (early winter), although atmospheric indicators are yet to fully align with an established El Niño event, according to Australia’s Bureau of Meteorology’s southern hemisphere monitoring report.
Uncertainty over strength
There remains some uncertainty as to the likely strength of the El Niño event. Models indicate this will be at least a moderate strength, with a potential for a strong event, depending on the amount of warming in the central tropical Pacific.
“Atmospheric indicators, including trade winds, pressure and cloud patterns in the tropical Pacific, are consistent with ENSO-neutral conditions but are also trending towards an El Niño state,” the report said.
Monsoon risk
In the past, El Nino events have led to either late arrival of the South-West Monsoon in India or deficient rain, besides prolonged dry spells. The India Meteorological Department (IMD) has predicted that it would be a below-normal monsoon this year, with the rainfall being 92 per cent of the long-period average.
Earlier this week, the IMD said the South-West Monsoon has lost its vigour, while a brewing storm may delay its onset over the Kerala coast. IMD had predicted the monsoon to set in on May 26.
In 2023, El Nino broke out in June and lasted for 11 months, affecting the Indian monsoon. It also resulted in 2024 being the warmest on record, as it continued until April 2024. It resulted in foodgrain crops, particularly paddy and pulses, being affected, leading to lower production. It also led to food inflation.
The Madden–Julian Oscillation is located in the Western Pacific, and model forecasts suggest it is likely to strengthen and continue propagating eastward into the Western Hemisphere during late May and early June. Such an event would also be associated with westerly wind anomalies over the western Pacific, which could further warm the tropical Pacific and reinforce the development of El Niño.
The Indian Ocean Dipole (IOD) is now neutral. The IOD index is -0.34°C (24 May 2026). The forecast state of the IOD is uncertain.
IOD outlook
The majority of models indicate the IOD is likely to remain neutral at least until early winter, with a positive IOD event possible in winter-spring (September). Model forecasts reveal a great deal of variability in the timing and magnitude of this potential event.
The Indian Ocean Dipole is a climate phenomenon that affects the Indian Ocean. In a positive phase, warm waters are pushed to the western part of the Indian Ocean. Cold deep waters are pushed up in the Eastern Indian Ocean. The pattern is reversed in the negative phase of the IOD.
Warm waters
The week ending 24 May 2026 sea surface temperature (SST) analysis shows waters are near average around much of Australia, except for the southeast and southwest, where SSTs are above average. Coastal waters of New South Wales and eastern Tasmania are particularly warm (about 3 to 4°C above average), the report added.
Published on May 26, 2026