Dried out. An El Nino event weakens India’s South West monsoon, often triggering drought-like conditions MUSTAFAH KK | Photo Credit: MUSTAFAH KK

All major climate models, including those used by Australia’s Bureau of Meteorology (BoM), project continued warming of the tropical Pacific, with El Nino possibly emerging between May and July.

While some models indicate an earlier onset, others suggest a more gradual transition, with uncertainty hinging on ocean-atmosphere coupling — a critical factor for sustaining a full-fledged El Nino.

Global climate signals are tilting towards a possible return of El Nino-Southern Oscillation (ENSO) warming later this year, even as near-term forecasts point to continued above-normal temperatures worldwide.

According to Australia’s Bureau of Meteorology, the ENSO system is currently in a neutral phase but is showing clear signs of warming. The latest Nino3.4 index, a key measure of Pacific Ocean temperatures, stood at -0.27°C for the week ending April 12, well within the neutral range.

However, the index has been steadily rising since the end of the southern hemisphere summer, supported by a recent pulse of sub-surface warming that is expected to lift sea surface temperatures further in the coming weeks.

Overall, climate models point to a warm global baseline with regionally varied rainfall patterns, while the growing likelihood of El Nino later in 2026 adds a layer of uncertainty to weather outcomes in the months ahead

Short-term atmospheric signals also reinforce the warming trend. The Madden-Julian Oscillation (MJO) is expected to bring westerly wind anomalies across the western Pacific in the coming fortnight, which typically enhances ocean warming.

Meanwhile, the 30-day Southern Oscillation Index has dropped sharply to -7.7, reflecting shifting pressure patterns across the Pacific, although longer-duration indices remain positive.

IOD neutral

Alongside ENSO, the Indian Ocean Dipole is currently neutral, with an index of +0.06°C. Most models suggest it will remain neutral through late autumn, though there is a growing possibility of a positive phase developing during winter and spring — a shift that can influence monsoon behaviour in the Indian subcontinent. Forecast uncertainty around the IOD remains elevated, with models showing a wide range of outcomes.

Against this evolving backdrop, the APEC Climate Center’s latest global seasonal outlook indicates that temperatures are likely to remain above average across most parts of the world in the coming months. The forecast, based on a multi-model ensemble approach, underscores a persistent warm bias in the global climate system.

On precipitation, the APCC outlook points to above-normal rainfall over India, the Maritime Continent, northern Australia and parts of the south-west Pacific, suggesting favourable moisture conditions for several regions. Warmer-than-average sea surface temperatures — forecast to be up to 2°C above normal around much of Australia and in the Tasman Sea — are expected to enhance atmospheric moisture and energise rainfall systems.

At the same time, some regions are projected to receive below-normal rainfall, highlighting the uneven distribution of global precipitation even under broadly warmer conditions.

For India, the combination of a neutral-to-warming ENSO phase and the possibility of a positive IOD later in the year could prove pivotal. While neutral ENSO conditions typically support stable monsoon patterns, a transition to El Nino — depending on its timing and strength — can alter rainfall distribution.

Published on April 21, 2026