Subscribe
The latter half of India’s southwest monsoon season this year could be affected by the super El Niño developing in the Equatorial Pacific Ocean, according to the long range forecast of the India Meteorological Department (IMD) on April 13. The southwest monsoon brings around 70 per cent of the annual rainfall, or around 870 mm (long period average or LPA) from June to September. IMD forecasts that the 2026 season may only see around 800 mm of rainfall. This could translate to adverse consequences for about 60 per cent farmers in the country reliant on monsoon rainfall for the kharif season.
The probability of a deficient season (rainfall below 90 per cent of LPA) is 35 per cent, more than double the long-term (climatological) probability of 16 per cent. Chances of a below normal season (90-95 per cent of LPA) is 31 per cent, and normal rainfall (96-104 per cent of LPA) is 27 per cent. The long-term probability of below normal rainfall is 17 per cent and of normal rainfall is 33 per cent. The chances of an above normal or excess rainfall are only 6 per cent and 1 per cent respectively.
The major climatic factors that could influence the rainfall are the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and the snow cover area in the Eurasian region. During the last super El Niño in 2015-16, IMD had predicted a southwest monsoon season with 93 per cent of LPA, which it later revised to 88 per cent. The actual rainfall recorded was 86 per cent of LPA, with widespread drought-like conditions across the country. The upcoming season projections show a similar bleak picture. Barring some regions in the extreme north such as Ladakh, extreme west such as Rajasthan, the Northeast and northern south peninsula such as Telangana, the rest of the country will see deficit rainfall.
The second driver, IOD, is a climatic phenomenon that occurs in the Indian Ocean. During its positive phase, western parts of the Indian Ocean are warmer than normal and eastern parts are cooler than normal, generally supporting good rainfall. These conditions are reversed during the negative phase, generally decreasing monsoon rains. IMD notes a neutral IOD in the Indian Ocean currently, with positive conditions forecast to develop by the end of the SWM. The third major factor is the snow cover over the northern hemisphere, especially the Eurasian region. IMD stated that the northern hemisphere snow cover extent from January to March was slightly below normal, which typically translates to a good monsoon.
Mrutyunjaya Mohapatra, director general of IMD, and M Ravichandran, secretary of the Union Ministry of Earth Sciences said in a media briefing on April 13 that development of positive IOD conditions and below normal snow cover over northern hemisphere could counter some impacts of the El Niño conditions. “We also forget that there is another major driver for monsoon rainfall, which is global warming. We have been observing excess moisture being added to the monsoon rainfall since 2000 and this accumulated moisture will be causing rainfall somewhere, such as what we have observed in Rajasthan in the past few years”, says K J Ramesh, climate scientist and former director general of IMD. “The worst-case scenario could be a slightly negative rainfall during the monsoon,” he adds.
This article was originally published in the May 1-15, 2026 print edition of Down To Earth