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The primary rainfall season for India, the South West Monsoon (SWM), could be below normal or deficient in 2026, according to the first long range forecast by the India Meteorological Department (IMD) issued on April 13, 2026. The major reason for this prediction is the expected El Niño conditions in the Equatorial Pacific Ocean by the second half of SWM.
This could be a major concern for around 60 per cent of farmers in the country who are completely dependent on monsoon rainfall for the Kharif cropping season. For many regions, this is a double whammy after facing losses during the stormy pre-monsoon season of 2026 due to hailstorms and flooding.
SWM is said to be below normal when the predicted rainfall for the season is 90-95 per cent of the long period average (LPA) for the country. The LPA for the monsoon is defined as the average rainfall between 1971-2020 and is around 868.6 mm.
“Quantitatively, the seasonal rainfall over the country as a whole is likely to be 92 percent of LPA which is around 800 mm with a model error of +/- 5 percent,” said IMD in a press release. In fact, the chances for a deficient rainfall with rainfall below 90 per cent of LPA is the highest at 35 per cent. The long term (climatological) probability of this occurrence is 16 per cent.
There is 31 per cent chance that the SWM in 2026 could be below normal (90-95 per cent of LPA) and a 27 per cent probability of a normal rainfall (96-104 per cent of LPA). The long-term chances of a below normal rainfall is 17 per cent and for normal rainfall is 33 per cent. The chances of an above normal or excess SWM are extremely rare — six per cent and one per cent respectively.
The major climatic factors that could influence the rainfall during SWM are the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and the snow cover area in the Eurasian region.
Currently, weak La Niña conditions are prevailing in the Equatorial Pacific Ocean and IMD predicts that the La Niña could transition to ENSO neutral conditions soon and remain in that phase between April to June.
The weather agency expects the development of warmer than normal El Niño conditions during SWM. El Niño conditions are known to generally suppress rainfall during SWM though experts highlighted that there have been some El Niño years with normal or above normal monsoon rainfall as well.
The IMD rainfall forecast map for the SWM across India paints a bleak picture for the upcoming cropping season. It shows that except for some regions in the extreme north, extreme west, northeast and northern south peninsula, the rest of the country is going to suffer from deficit rainfall.
The IOD is a climatic phenomenon which occurs in the Indian Ocean and affects monsoon rainfall. During the positive phase of the IOD, the western parts of the Indian Ocean are warmer than normal and the eastern parts are cooler than normal. During the negative phase, the conditions are reversed.
The positive phase of the IOD generally supports good monsoon rainfall while the negative phase generally decreases monsoon rains. IMD said that currently, neutral IOD conditions are prevalent in the Indian Ocean and forecast the development of positive IOD conditions by the end of the SWM.
The third major driver of SWM is the snow cover over the northern hemisphere, especially the Eurasian region. The weather agency stated that the northern hemisphere snow cover extent during the last three months (January to March 2026) was slightly below normal. When the snow cover over the northern hemisphere, including over Eurasia is below normal, good rainfall is observed during the SWM, according to IMD.
Mrutyunjaya Mohapatra, director general of IMD, and M Ravichandran, secretary of the Union Ministry of Earth Sciences both told reporters during a press conference at Mausam Bhavan that the development of positive IOD conditions in the latter part of SWM and the below normal snow cover over northern hemisphere could counter some of the 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,” K J Ramesh, climate scientist and former director general of IMD told Down To Earth.