How Accurate Are Monsoon Forecasts? ‘Below-Normal’ Warning Revives Old Concerns
IMD and Skymet’s below-normal 2026 monsoon forecast underscores persistent concerns over the accuracy and reliability of India’s rainfall predictions.
Published : April 14, 2026 at 8:00 PM IST
New Delhi: India’s 2026 southwest monsoon forecast has once again brought into focus a long-standing question of how reliable the monsoon predictions are and how much India can depend on those.
With the India Meteorological Department (IMD) projecting rainfall at 92 percent of the Long Period Average (LPA), categorised as below normal, and private forecaster Skymet Weather warning of a weak season, concerns are rising across agriculture, policy circles, and markets.
El Niño Threat Looms Large
The biggest driver behind the cautious forecast is the possible return of El Niño, a climate pattern known to disrupt India’s monsoon.
The potential of an El Niño forming during the monsoon months is approximately 50 percent to 60 percent (Global and Indian Models). Some models have a likelihood of developing El Nino that are predicted to occur during the latter part of the monsoon season and possibly gain strength.
This is concerning as it appears that 70 percent of El Niño years occurring since 1980, have had weak monsoon seasons in India. Major drought years for India such as 2002 and 2009 coincided with the occurrence of El Nino conditions.
The 2026 forecast is suggesting that the risk for El Nino is more than normal for 2026 and that the national climate is expected to receive below normal precipitation and greater than 45 percent to 65 percent probability of Sub-Optimal precipitation or insufficient rainfall in the central portion of India, which generally includes the major agricultural growing regions for the country.
The monsoon prediction continues to be classified as a Forecast of Probabilities, even with advances in Climate Science, forecasting Monsoon weather is inherently uncertain.
The IMD itself acknowledges that long-range forecasts are probabilistic. Even globally, experts warn that spring forecasts of El Niño are less reliable due to the “spring predictability barrier”, a known limitation in climate modelling.
India’s Monsoon Influenced By Multiple Factors
- Pacific Ocean temperatures (ENSO cycle)
- Indian Ocean Dipole
- Eurasian snow cover
- Land–atmosphere feedback
This complexity makes it difficult to predict not just the total rainfall but its distribution and timing, which are far more critical for farmers.
Accuracy Record
According to Ministry of Earth Sciences, data over the past decade shows incremental improvement in forecasting models, with IMD deploying better dynamical models and data assimilation systems. However, accuracy is still uneven.
Both IMD and private agencies have frequently missed rainfall intensity even when predicting the correct category. Skymet, while outperforming IMD in some earlier years, has shown less consistent performance recently (Ministry of Earth Sciences data).
Why It Matters?
- Nearly 70 percent of India’s agriculture depends on monsoon rains
- Around 40 percent of the workforce is linked to agriculture (Ministry of Earth Sciences data)
- A weak monsoon can trigger food inflation, rural distress, and slower GDP growth
Economists warn that a below-normal monsoon could
- Push inflation above comfort levels
- Reduce crop output (especially rice, sugar, pulses)
- Increase import dependence (like edible oils)
Forecast Vs Reality Gap
One of the biggest issues is the gap between seasonal forecasts and ground reality.
Even in years with “normal” rainfall-
Rainfall may be uneven (heavy in some regions, deficient in others)
Long dry spells can damage crops despite normal totals
Extreme events (floods, cloudbursts) are rising but hard to predict
Recent research also shows that extreme rainfall events are harder to forecast than seasonal averages, limiting the usefulness of predictions for disaster preparedness.
Yet, despite limitations, monsoon forecasts remain critical. They guide in crop planning and sowing decisions, reservoir and water management, government contingency planning and commodity and financial markets. Even an imperfect forecast helps policymakers prepare for risks like drought, inflation, and supply shocks.
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