El Niño Returns? Decoding the 2026 Monsoon Forecast

How the Monsoon Works

The south-west monsoon is a seasonal reversal of winds driven by differential heating of land and sea, the northward shift of the Inter-Tropical Convergence Zone, the Tibetan Plateau's heat low, and the Somali Jet that pushes moisture-laden winds across the Arabian Sea. The Tropical Easterly Jet and the position of the monsoon trough modulate active and break phases.

• Onset over Kerala is normally around 1 June; the monsoon covers the country by about 8 July.
• IMD's Long Period Average (LPA) for June–September is 87 cm (1971–2020 base); 96–104 per cent of LPA is 'normal'.
• About 70 per cent of India's annual rainfall arrives in these four months; roughly half of net sown area is rain-fed.

El Niño, IOD and Other Drivers

• ENSO: El Niño (warm eastern Pacific) weakens the Walker circulation and typically suppresses Indian monsoon rainfall; La Niña enhances it. About 60 per cent of El Niño years saw deficient monsoons.
• Indian Ocean Dipole: a positive IOD (warmer western Indian Ocean) can offset El Niño, as in 1997.
• Eurasian snow cover: heavier winter snow weakens the summer land–sea thermal contrast.
• Madden–Julian Oscillation: an eastward-moving tropical pulse that governs intra-seasonal active and break spells.

Implications

A weak monsoon lowers kharif sowing of paddy, pulses and oilseeds, tightens reservoir levels for rabi irrigation and pushes food inflation — all watched closely by the RBI. Contingency plans include short-duration seed varieties, staggered sowing advisories through Gramin Krishi Mausam Sewa, and activating drought codes under the 2016 Manual for Drought Management.