El Nino Casting Shadow Over Southwest Monsoon 2026

Key Takeaways:

• El Niño is emerging and may become one of the strongest in recent decades
• 61% probability of development during May–July 2026
• Likely to impact global weather with floods and drought extremes
• India may see below-normal southwest monsoon rainfall

El Niño, an ocean-atmosphere coupled phenomenon, is in the nascent stage over the equatorial Pacific. It is expected to start influencing global weather patterns commencing the summer of the Northern Hemisphere and continuing till winters over the North American continent. Forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF), Climate Prediction Center (NOAA), and other experts suggest that it could evolve into one of the strongest events of the last few decades.

The higher sea surface temperatures over the Niño region in the equatorial Pacific and the weaker trade winds lead to different weather patterns in different parts of the world. It is quite likely to redraw the global pattern, triggering massive floods in some areas and severe droughts in other pockets. It may even alter storm patterns in both the Atlantic and Pacific Oceans.

Usually, over the Indian subcontinent, an El Niño event leads to depletion of southwest monsoon rainfall and an increase in the northeast monsoon season. There are conclusive indications of a quick collapse of the ongoing weak La Niña, a brief transition to ENSO-neutral, followed by the emergence of a strong El Niño over the far eastern Pacific Ocean.

ENSO: How El Niño starts and how it gets terminated has always been a contentious issue and, by and large, remains a mystery. What leads to a rise in equatorial Pacific temperatures is nearly inexplicable. Associated changes in trade winds and ocean-atmosphere coupling are a by-product. However, the initiation of the process itself remains a puzzle.

The upper ocean heat anomalies in the Pacific Ocean are warmer than average. Sub-surface temperatures have also steadily increased over the last quarter (Jan–Mar). The Niño index has remained between -0.2°C and -0.3°C over the last three weeks. The latest ENSO update from the CPC, as of April 13, 2026, indicates a 61% chance of El Niño developing during May–July 2026. The event could last until the end of 2026 and may even spill over into the next year.

IOD: The Indian Ocean Dipole has remained neutral for the last four weeks. The latest index value for the week ending April 13, 2026, was +0.06°C. The IOD has a tendency to turn positive during El Niño events. IOD-induced surface wind anomalies can produce El Niño-like SST anomalies, with a strong effect in the far-eastern Pacific. A strong positive IOD can also partially offset the adverse effects of El Niño on monsoon rainfall.

MJO: The Madden–Julian Oscillation is a key intra-seasonal tropical atmospheric disturbance that significantly modulates the Indian monsoon. Its active phase (Phases 2–4) brings heavy rainfall to India, while the suppressed phase (Phases 6–8) causes dry spells. A shorter MJO cycle supports better rainfall, whereas its presence over the Pacific, especially during El Niño, can disrupt the monsoon. The MJO pulse is fairly strong and will move across the Western Hemisphere and Africa, between Phases 8 and 2, during the second half of April.

El Niño-centric monsoon forecasts by most weather agencies are indicating a ‘below normal’ season during June–September. MJO is a transient parameter with a highly uncertain cycle duration, while IOD forecasts lack accuracy beyond a lead time of eight weeks. However, both MJO and IOD will play a crucial role amid speculation of a strong El Niño during the monsoon season.