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INCOIS assesses that El Nino conditions, which developed in May 2026, are likely to persist from June 2026 to February 2027 with forecast probabilities of 70 to 90 per cent.
IMD's First Stage Long Range Forecast of 13 April 2026 put seasonal rainfall at 92 per cent of the Long Period Average, revised in the Second Stage forecast to 90 per cent.
Since 1950 there have been 16 El Nino years, of which only 7 saw below-normal Indian monsoon rainfall - and the inverse relationship is strongest in the later half of the season, particularly September.
El Nino is not the sole determinant: the Indian Ocean Dipole, the Madden-Julian Oscillation and regional ocean-atmosphere interactions also shape the monsoon.
Mission Mausam is strengthening climate modelling, satellite observation, atmospheric research and numerical weather prediction, including more Doppler Weather Radars and automatic weather stations.
El Nino is the warm phase of the El Nino Southern Oscillation, a coupled ocean-atmosphere cycle in the tropical Pacific. In its warm phase the eastern and central Pacific warm, trade winds weaken and the main zone of atmospheric convection shifts eastward, away from the Indian Ocean - which tends to suppress the ascending limb of the circulation that drives the Indian summer monsoon. Hence the association with weaker rainfall. But the reply is careful, and the historical record explains why: of 16 El Nino years since 1950, only 7 produced below-normal Indian rainfall. Fewer than half. The monsoon has several drivers, and a positive Indian Ocean Dipole - warmer western than eastern Indian Ocean - can offset El Nino entirely, while the Madden-Julian Oscillation modulates rainfall on a 30-60 day cycle within the season. Forecasts are expressed against the Long Period Average, the long-run mean seasonal rainfall, so '90 per cent of LPA' means a tenth below the historical norm, and the stated model error - plus or minus 4 or 5 per cent - is as important as the central figure. Note also the seasonal asymmetry the reply flags: the inverse relationship with El Nino is stronger in the second half of the monsoon, particularly September, which matters for late-sown crops and reservoir filling.
Simple Analogy: El Nino tilts the odds against a good monsoon; it does not decide the outcome, because several other players are also at the table.
Create an integrated framework strengthening climate modelling, satellite observations, atmospheric research and numerical weather prediction, to improve understanding of changing monsoon patterns and extreme weather.
Key: Adopts advanced Multi-Model Ensemble and coupled dynamical climate models for operational long-range forecasting at monthly and seasonal scale.
Improve forecast accuracy through better model physics, higher spatial resolution and advanced data assimilation.
Key: Supported by enhanced computational capability.
Densify ground and upper-air observation.
Key: Additional Doppler Weather Radars, a lightning network, Automatic Weather Stations, Automatic Rain Gauges, upper-air observing systems and wind profilers.
Forecast storm surge, high waves, swell surge and high currents.
Key: Delivered by INCOIS through an ocean observation network of gliders, moored buoys, Argo floats, tide gauges and satellite observations with advanced data assimilation.
Issues seasonal and monthly rainfall and temperature forecasts, the Long Range Forecasts for the southwest monsoon, daily monsoon updates and monthly El Nino updates, and rainfall data at district and block level.
Produces the ENSO assessment using an indigenous AI/ML-based prediction system with the Global Ocean Data Assimilation System, and runs Ocean State Forecasting and marine multi-hazard early warning.
Works with agriculture and dam management departments to translate seasonal and medium-range forecasts into impacts for farming and water management.
Receives near-real-time satellite observations from global providers including NASA/NOAA, ESA/EUMETCast, CMA, KMA and JMA, alongside ISRO and IMD data, for assimilation into forecast models.
GS Paper 1 > Geography: Climatology, Indian Monsoon; GS Paper 3 > Environment and Disaster Management
General Awareness > Geography and Environment
General Awareness > Economy and Agriculture
General Awareness > Geography
With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct? 1. IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean. 2. An IOD phenomenon can influence an El Nino's impact on the monsoon. Select the correct answer using the code given below:
Answer: 2 only
El Nino, the Indian Ocean Dipole and monsoon forecasting are among the most repeated geography and environment topics across UPSC, SSC and Railway exams.
El Nino Southern Oscillation - the coupled ocean-atmosphere cycle in the tropical Pacific, of which El Nino is the warm phase.
The long-run mean seasonal rainfall against which IMD expresses its forecasts; 90 per cent of LPA means a tenth below the historical norm.
The difference in sea surface temperature between the western and eastern Indian Ocean; a positive IOD can offset El Nino's suppressing effect on the monsoon.
An eastward-moving disturbance that modulates tropical rainfall on a roughly 30-60 day cycle within the monsoon season.
A forecasting approach combining several models to improve long-range seasonal prediction, adopted under Mission Mausam.
A free-drifting ocean profiling instrument measuring temperature and salinity, part of INCOIS's observation network.