What Happened
- The India Meteorological Department (IMD) issued its first long-range forecast on April 13, 2026, predicting that India's southwest monsoon (June–September 2026) will be below normal at 92% of the Long Period Average (LPA) with a model error of ±5%.
- The LPA of southwest monsoon rainfall for the period 1971–2020 is 87 cm; a 92% forecast translates to approximately 80 cm of rainfall.
- The primary driver of the below-normal forecast is the expected development of El Niño conditions in the equatorial Pacific Ocean during the second half of the monsoon season (August–September).
- There is a 35% probability of a deficient monsoon (below 90% of LPA) and 31% probability of below-normal monsoon (90–95% of LPA); together they represent a 66% chance of an adverse season.
- A positive Indian Ocean Dipole (IOD) could develop in the second half of the season and partially mitigate El Niño's suppressive effect, as seen in 1997 and 2019.
Static Topic Bridges
Southwest Monsoon: Mechanism and Classification
The southwest monsoon (June–September) is India's primary rainfall season, driven by differential heating of land and sea. As the Asian landmass heats rapidly in summer, low pressure develops over the subcontinent, drawing moisture-laden winds from the Indian Ocean and the Arabian Sea northward — the classic sea-to-land pressure differential.
- The IMD classifies monsoon seasonal rainfall relative to the LPA: Deficient (below 90%), Below Normal (90–95%), Normal (96–104%), Above Normal (105–110%), Excess (above 110%).
- The southwest monsoon delivers approximately 75% of India's total annual rainfall, making it the decisive climatic event for agriculture, groundwater recharge, river flow, and reservoir levels.
- The monsoon has two branches: the Arabian Sea branch (hits Kerala first, then moves northward) and the Bay of Bengal branch (enters northeast India and moves westward).
- India's National Long Range Forecast is issued by IMD in April (first forecast) and updated in May.
Connection to this news: The 2026 below-normal forecast at 92% of LPA is not statistically extreme, but the probability distribution skewed toward "deficient" (35%) makes agricultural planning and water resource management critically important.
El Niño and the Indian Ocean Dipole
El Niño is the warm phase of the El Niño–Southern Oscillation (ENSO) — a periodic warming of sea surface temperatures in the central and eastern equatorial Pacific Ocean. This warming weakens the Walker Circulation and shifts rainfall patterns globally, typically reducing monsoon rainfall over India.
- Historically, 12 out of 15 El Niño years saw a contraction in India's total food grain production; oilseed output contracted in 13 out of 15 El Niño years.
- The Indian Ocean Dipole (IOD) is a coupled ocean-atmosphere phenomenon defined by a difference in sea surface temperature between the western (Arabian Sea) and eastern (Bay of Bengal) Indian Ocean. A positive IOD (warmer western Indian Ocean) enhances rainfall over India and can offset El Niño's suppressive effect.
- The 2019 monsoon was near-normal despite El Niño partly because a strong positive IOD developed.
- A 1% change in annual monsoon rainfall is estimated to cause a 0.34% change in India's agricultural GDP.
Connection to this news: The IMD's "no cause for alarm" messaging for 2026 is partly based on the possibility of a positive IOD developing later in the season — but the window of uncertainty remains wide until May updates.
Monsoon and India's Food-Agriculture Nexus
India's agricultural economy is structurally dependent on monsoon rainfall. Approximately 60% of India's net sown area is rainfed, meaning it has no access to irrigation and is entirely dependent on seasonal rainfall.
- Rainfed agriculture accounts for 40% of total food grain production and 85% of nutri-cereals (millets), 83% of pulses, 70% of oilseeds, and 65% of cotton.
- Kharif crops — rice, maize, soybean, cotton, pulses — are sown at the onset of monsoon (June–July) and harvested in September–October; they are the most vulnerable to monsoon deficits.
- Agriculture contributes approximately 18% of GDP and employs 45% of India's workforce; poor monsoons directly affect rural incomes, food inflation (especially pulses and oilseeds), and government fiscal management through higher input subsidies and food imports.
- National Food Security Act 2013 commits India to providing subsidised foodgrains to 67% of the population — a below-normal monsoon puts pressure on buffer stocks and the PDS (Public Distribution System).
Connection to this news: A below-normal 2026 monsoon risks higher food inflation (particularly pulses and edible oils), lower kharif output, and potential pressure on India's current account through higher agricultural imports.
Key Facts & Data
- 2026 southwest monsoon forecast: 92% of LPA (±5%), i.e., approximately 80 cm vs. LPA of 87 cm
- IMD classification thresholds: Deficient < 90% LPA; Below Normal 90–95%; Normal 96–104%
- Probability breakdown: 35% deficient, 31% below-normal, 34% normal-to-excess combined
- 75% of India's annual rainfall comes from the southwest monsoon (June–September)
- ~60% of India's net sown area is rainfed
- A 1% monsoon deficit → ~0.34% drop in agricultural GDP
- Historical precedent: food grain contraction in 12 out of 15 El Niño years
- LPA (1971–2020 base period): 87 cm for June–September