El Niño threat: South Asia braces for below-average monsoon in 2026, says climate forum

The 34th Session of the South Asian Climate Outlook Forum (SASCOF-34), held on 28 April 2026 in Malé, Maldives, issued a seasonal monsoon forecast predicting...

What Happened

The 34th Session of the South Asian Climate Outlook Forum (SASCOF-34), held on 28 April 2026 in Malé, Maldives, issued a seasonal monsoon forecast predicting below-normal rainfall for most of South Asia during the June–September 2026 southwest monsoon season.
Climate experts from nine South Asian countries' National Meteorological and Hydrological Services (NMHSs), along with the World Meteorological Organization (WMO) and partner agencies, reached a consensus that El Niño conditions are likely to develop during the 2026 monsoon season.
The strongest below-normal rainfall signal is projected over central parts of South Asia; however, parts of north-western, north-eastern, and southern South Asia may experience normal to above-normal rainfall.
The Indian Ocean Dipole (IOD) is expected to move from neutral to positive phase during the season — a development that could partially counteract El Niño's suppressive effect on the monsoon.
Both maximum daytime and minimum overnight temperatures are expected to be above normal across the region during the monsoon period.
The WMO estimates El Niño conditions will likely emerge by May–July 2026.

Static Topic Bridges

El Niño-Southern Oscillation (ENSO) — Mechanism and Monsoon Impact

ENSO (El Niño-Southern Oscillation) is the dominant year-to-year driver of global climate variability, originating in the tropical Pacific Ocean. Under normal (La Niña or neutral) conditions, strong easterly trade winds push warm surface water westward across the Pacific, building a warm pool near Indonesia and Australia. This warm pool drives intense convection and rising air, which fuels the Asian monsoon system.

During an El Niño event, the trade winds weaken and warm water spreads eastward toward South America. This shifts the centre of atmospheric convection from the western Pacific to the central/eastern Pacific, weakening the Walker Circulation — the large-scale east-west atmospheric loop that connects the Pacific to the Indian Ocean. The consequence for South Asia: suppressed convection, reduced moisture flux, and below-normal monsoon rainfall.

El Niño events cause below-normal monsoon rainfall in India in approximately 60% of El Niño years (though not all El Niño years result in deficient monsoons).
ENSO is measured using the Oceanic Niño Index (ONI) — the 3-month running average of SST anomalies in the Niño 3.4 region (5°N–5°S, 120°–170°W). An El Niño is declared when the ONI is ≥+0.5°C for five consecutive overlapping 3-month periods.
The Southern Oscillation refers to the atmospheric pressure seesaw between the western Pacific (Darwin, Australia) and the eastern Pacific (Tahiti), measured by the Southern Oscillation Index (SOI). Negative SOI values correspond to El Niño.
Historically significant El Niño-linked drought years in India: 1877, 1899, 1918, 1972, 1987, 2002, 2009.

Connection to this news: The SASCOF-34 consensus projection of El Niño development during June–September 2026 directly explains the forecast of below-normal monsoon rainfall across most of South Asia.

Indian Ocean Dipole (IOD) — India's Counterweight to ENSO

The Indian Ocean Dipole (IOD) is an ocean-atmosphere interaction phenomenon in the Indian Ocean, characterised by anomalous sea surface temperature (SST) differences between the western and eastern Indian Ocean. It is measured by the Dipole Mode Index (DMI), which calculates the SST difference between the western Indian Ocean (50–70°E, 10°S–10°N) and the eastern Indian Ocean near Sumatra (90–110°E, 10°S–0°N).

A positive IOD (western Indian Ocean warmer than eastern Indian Ocean) enhances moisture flux toward South Asia and typically results in 10–20% above-normal rainfall over India. A negative IOD has the opposite effect. The IOD is largely independent of ENSO, though interactions exist.

The 2019 monsoon provides a landmark case: despite a moderate El Niño in the Pacific, a strong positive IOD compensated, yielding above-normal monsoon (110% of Long Period Average, LPA).
The IOD was first identified as a distinct climate phenomenon in a 1999 study by Saji et al., published in Nature.
A neutral-to-positive IOD phase in 2026, as projected by SASCOF-34, may partially mitigate El Niño's suppressive impact but is unlikely to fully offset it.
IMD (India Meteorological Department) monitors IOD alongside ENSO in its seasonal monsoon forecasts, issued each April and updated in May.

Connection to this news: SASCOF-34 notes that while the IOD is expected to shift positive, the dominant driver this season is El Niño — the net effect is a below-normal monsoon signal across most of South Asia.

South Asian Climate Outlook Forum (SASCOF) — Institutional Framework

SASCOF is a regional climate forum established under the auspices of the World Meteorological Organization (WMO) to produce consensus-based seasonal climate outlooks for South Asia. It is convened annually before the southwest monsoon season (typically April–May), with participating agencies from Bangladesh, Bhutan, India, Iran, Maldives, Myanmar, Nepal, Pakistan, and Sri Lanka.

The WMO Regional Climate Centre (RCC) at the India Meteorological Department (IMD), Pune, serves as a key technical hub for SASCOF. The forum draws on model outputs from multiple global seasonal prediction centres, including the UK Met Office, Japan Meteorological Agency, and the WMO Lead Centre for Seasonal Prediction.

WMO established: 1950 (as the intergovernmental successor to the International Meteorological Organization, est. 1873); headquarters: Geneva, Switzerland; 193 member states.
SASCOF-34 (April 28, 2026): held in Malé, Maldives; ninth South Asian country represented.
India Meteorological Department (IMD): established 1875; nodal agency for weather forecasting in India; under Ministry of Earth Sciences.
Long Period Average (LPA) for Indian monsoon: 87 cm of rainfall over the June–September season (based on 1971–2020 average); below-normal defined as <96% of LPA.
IMD seasonal forecast (April 2026): predicts below-normal monsoon for India — consistent with SASCOF-34 projection.

Connection to this news: SASCOF-34's multilateral consensus forecast carries authoritative weight because it aggregates multiple model outputs and expert assessments from across South Asia, giving it higher confidence than any single national forecast.

Monsoon Mechanism — Southwest Monsoon and ITCZ

The Indian Southwest Monsoon (June–September) is driven by the differential heating of the Asian landmass and the Indian Ocean. As the subcontinent heats up in summer, a thermal low develops over Rajasthan and Pakistan; this draws in moisture-laden winds from the warm southwest Indian Ocean, triggering intense rainfall across India.

The Intertropical Convergence Zone (ITCZ) — the belt of low pressure near the equator where northeast and southeast trade winds converge — migrates northward in summer, reaching over the Indian subcontinent and providing the dynamic support for monsoon onset. El Niño weakens the Walker Circulation, reducing the pressure gradient that drives the ITCZ northward and thus suppressing monsoon onset and intensity.

Southwest monsoon onset at Kerala: normal date is June 1 (±7 days); delayed onset is one of the early signals of a deficient monsoon year.
The Arabian Sea branch and Bay of Bengal branch of the southwest monsoon are the two main arms; the Bay of Bengal branch is more active in terms of rainfall volume.
Normal monsoon season (June–September): accounts for ~75% of India's total annual rainfall.
Agriculture dependency: ~50% of India's net sown area relies on monsoon rainfall (rainfed agriculture); kharif crops — rice, jowar, bajra, cotton, groundnut, soybean — are critically monsoon-dependent.
Below-normal monsoon triggers food security concerns, inflation (food price pressure), rural distress, and impacts hydropower generation and reservoir levels.

Connection to this news: The agriculture and food security implications of a below-normal monsoon are the primary policy concern — affecting kharif crop output, rural incomes, and headline inflation, all of which are UPSC mains themes.

Key Facts & Data

SASCOF-34 session date: 28 April 2026; venue: Malé, Maldives
Forecast: Below-normal monsoon (June–September 2026) over most of South Asia, especially central parts
Climate drivers: El Niño (likely to develop May–July 2026) + neutral-to-positive IOD
WMO headquarters: Geneva, Switzerland; members: 193 states
IMD established: 1875; nodal ministry: Ministry of Earth Sciences
India's Long Period Average (LPA) for monsoon: 87 cm (June–September); based on 1971–2020 data
El Niño defined as: ONI ≥ +0.5°C for 5 consecutive overlapping 3-month periods in Niño 3.4 region
IOD measured by: Dipole Mode Index (DMI) — western minus eastern Indian Ocean SST anomaly
El Niño–monsoon link: below-normal rainfall in India in ~60% of El Niño years
2019 precedent: Strong positive IOD offset moderate El Niño → monsoon at 110% of LPA
Kharif crop season: June–October (sown at monsoon onset, harvested post-monsoon)
~75% of India's annual rainfall occurs in the June–September monsoon season