A few members of the ensemble are forecasting a “super” El Nino late in 2026.

Drought-bearing El Nino has set in, while a positive IOD will emerge by July (boreal summer), the Japanese weather agency JAMSTEC has said.

“As predicted earlier, an El Nino occurred,” JAMSTEC said on Thursday. It is the first agency to declare the arrival of the climatic pattern.

JAMSTEC’s predictive model, SINTEX-F, forecasts a further development of El Nino towards a strong El Nino in boreal summer, between June and August. A few members of the ensemble are forecasting a “super” El Nino late in 2026.

Indian Ocean Dipole

The tropical Indian Ocean is currently in a neutral state, SINTEX-F said. The model predicts a positive Indian Ocean Dipole (IOD) event in the boreal midsummer (July).

​A positive IOD can bring more moisture to India, often helping monsoon rains even in an El Nino year. IOD is a climate phenomenon caused by variations in sea temperatures in the Indian Ocean. Its positive, negative and neutral phases can influence the Indian monsoon.

The development comes on the heels of the India Meteorological Department (IMD) lowering its forecast for the South-West Monsoon to receive 90 per cent of the long-period average rainfall. The monsoon has arrived 3 days late this year on the Kerala coast on June 4.

SINTEX-F (Scale Interaction Experiment-Frontier) is a coupled ocean-atmosphere climate prediction system developed by JAMSTEC in collaboration with European partners.

Regional forecast

The model predicts hotter-than-normal conditions for much of the globe during the July–September average.

Relatively high signal-to-noise ratios are observed in the western United States, Mexico, Central America, most of South America (excluding Argentina and southern Chile), New Zealand, southern and western Australia, most of Africa, most of the Middle East, some parts of Europe, Turkey, Indonesia, Papua New Guinea, many islands in the tropical Pacific, most of Southeast Asia, India, Mongolia, some of China, and Hawaii, the report added.

Signal-to-noise ratio

Meteorologists use the signal-to-noise ratio (SNR) to help them determine how much of the data they get from the atmosphere is signal (good information) and how much is noise (random background interference). If the SNR is high, it means the real weather trend is obvious

The report said southwestern Polynesia will be cooler-than-normal. The model shows above-normal temperatures for much of the globe during the boreal autumn (October).

Drier-than-normal conditions are forecast across Central America, the Caribbean, western Brazil, eastern Australia, parts of East Africa, parts of western equatorial Africa, Yemen, Nepal, North India, Malaysia, Indonesia and some islands in the southern tropical Pacific during July–September.

In particular, Indonesia and eastern Australia could experience conditions much drier than normal due to a combination of the positive Indian Ocean Dipole and El Nino.

The JAMSTEC forecast predicts wetter-than-normal conditions across parts of Southeast Asia and some islands in the Western and Northern Tropical Pacific.

October is expected to be drier than normal for the Caribbean, most of Brazil, Indonesia, the Philippines, eastern Australia, India, some of East Africa, southern Africa and some islands in the southern tropical Pacific.

Some islands in the western and northern tropical Pacific, the Maldives, the Democratic Republic of the Congo and parts of Eurasia are expected to experience wetter-than-normal conditions.

The model predicts that most of Japan will experience hotter-than-normal temperatures between September and November.

Published on June 11, 2026