A Possible El Niño in 2026: What It Could Mean for the Indian Monsoon

Every year, the Indian monsoon is watched closely—not only by meteorologists, but by farmers, water managers, disaster agencies, businesses, and millions of ordinary citizens. The southwest monsoon provides nearly 70–80% of India’s annual rainfall (Figure 1) and supports agriculture, water resources, energy production, and livelihoods. This year, growing discussions around the possible development of an El Niño in the Pacific Ocean have raised an important question: Will El Niño affect India’s monsoon in 2026?


Figure 1: Average monsoon season (June-September) rainfall (left panel) and Percentage of annual rainfall during monsoon season (right panel)

The short answer is: possibly, but not always in a straightforward way. To understand what may happen, it is useful to look at the science behind El Niño, its historical relationship with the Indian monsoon, and why modern forecasting is more nuanced than simple cause-and-effect.

What is El Niño?

The El Niño–Southern Oscillation (ENSO) is one of the most important climate phenomena influencing weather worldwide, including in India. It has three phases: El Niño, La Niña, and neutral conditions.

El Niño refers to the abnormal warming of sea surface temperatures over the central and eastern equatorial Pacific Ocean. This warming alters atmospheric circulation across the tropics and affects global rainfall, temperatures, and other factors. For India, El Niño is especially important because it can influence the strength and distribution of the southwest monsoon. Historically, many drought years in India have coincided with El Niño events (Figure 2). However, not every El Niño leads to drought, and not every drought is caused by El Niño. That distinction is crucial.

Figure 2: Composite rainfall anomaly (mm) for El Niño and La Niña during the period 1961-2020.

How does El Niño affect the Indian monsoon?

The Indian monsoon is driven by land-sea thermal contrast and large-scale atmospheric circulation. During El Niño years, changes in tropical Pacific heating can weaken the large-scale circulation that supports monsoon rainfall over South Asia. In simple terms, during El Niño, a warmer Pacific Ocean alters tropical convection -> atmospheric circulation shifts eastward -> monsoon circulation over India may weaken -> rainfall can reduce.

This teleconnection between the Pacific and Indian monsoon has been recognized for decades and remains one of the key predictors in seasonal forecasting. But the relationship is not always uniform. Does El Niño always mean below-normal monsoon? No. This is one of the biggest misconceptions. Several El Niño years in recent decades have indeed been associated with deficient monsoon rainfall over India, such as 2002, 2009, and 2015. These years saw significant rainfall deficits and widespread agricultural impacts. At the same time, some El Niño years, such as 1997 and 2023, have not resulted in severe monsoon failure.
Figure: Rainfall anomaly map shows how the Indian summer monsoon rainfall (June–September) departed from normal during past El Niño years in the recent decades between 1981 and 2025. Red shades represent below-normal rainfall, and Green shades represent above-normal rainfall

Why? Because the monsoon is influenced by multiple climate drivers, not just ENSO. Other important climate modes include the Indian Ocean Dipole (IOD), Madden–Julian Oscillation (MJO), Snow cover over Eurasia, Land surface processes, Regional sea surface temperature patterns, etc. For example, a positive IOD can sometimes offset the negative influence of El Niño by enhancing moisture transport toward India. This means the final monsoon outcome depends on the combined interaction of several climate factors.

What are climate models indicating for 2026?

Many global climate models and operational forecasting systems are indicating a possible transition toward El Niño conditions during the monsoon season of 2026. In addition, the seasonal outlook issued by the India Meteorological Department suggests a tendency toward below-normal monsoon rainfall over India, which is broadly consistent with the evolving large-scale ocean–atmosphere conditions. While this forecast provides an important early signal, it should be interpreted in probabilistic terms rather than as a deterministic outcome. Seasonal prediction has improved significantly over the years, but uncertainty remains. 


Figure: Probabilistic forecast of ENSO issued in April 2026 (Source: https://iri.columbia.edu/)


Figure: Probabilistic forecast of rainfall over India for the 2026 monsoon season (June-September) issued in April 2026 (Source: https://mausam.imd.gov.in/)

Three factors are especially important:

Timing of El Niño development: An El Niño developing before or during the monsoon onset may have a stronger impact.

Intensity of warming: A weak El Niño may not produce strong monsoon suppression, but at the same time, a strong El Niño may not lead to strong monsoon suppression. 

Interaction with the Indian Ocean: The state of the Indian Ocean can either reinforce or weaken ENSO impacts.

This is why operational agencies such as the India Meteorological Department continuously monitor evolving ocean-atmosphere conditions and update seasonal forecasts.

What could be the possible monsoon scenario?

If El Niño strengthens during the core monsoon season, some possible outcomes may include:

Reduced seasonal rainfall: There could be a tendency toward below-normal rainfall at the all-India scale. However, regional differences are important. Some regions may still receive normal or above-normal rainfall.

Increased dry spells: Even if seasonal rainfall totals are near normal, the distribution may become uneven. Long dry spells between rainfall events can stress agriculture.

Higher temperature conditions: El Niño years are often associated with warmer-than-normal temperatures, which can increase evapotranspiration and water demand.

Increased rainfall variability: Extreme rainfall events can still occur. A weaker seasonal monsoon does not necessarily mean fewer heavy rainfall events. This is important for flood and urban drainage management. 

Why does this matter for society?

The monsoon is not just a weather system—it is the backbone of India’s economy. The below-normal monsoon may affect many climate-sensitive sectors in India.

(a) Agriculture: Agriculture remains highly dependent on monsoon rainfall, especially rainfed farming. Delayed onset, reduced rainfall, or prolonged dry spells can affect sowing, crop growth, and yield. Farmers may need contingency planning.

(b) Water resources: Reservoir inflows, groundwater recharge, and river flows depend heavily on monsoon rainfall. Deficient rainfall can stress water availability for drinking, irrigation, and hydropower.

(c) Energy: Hydropower generation may be affected in low rainfall scenarios. At the same time, higher temperatures can increase electricity demand.

(d) Health: Warmer conditions and altered rainfall patterns can influence heat stress and disease transmission patterns.

(e) Disaster management: Even in weak monsoon years, short-duration heavy rainfall events can trigger floods and landslides. Preparedness remains essential.

The monsoon outlook for 2026 will become clearer as we move closer to the season. Key indicators to monitor include: Evolution of Pacific sea surface temperatures, Subsurface ocean heat content, Atmospheric circulation patterns, Indian Ocean conditions, Updated seasonal forecasts, etc. Regular forecasts will be updated from the India Meteorological Department.

Final thoughts

The possible emergence of El Niño in 2026 is an important development for monsoon monitoring and preparedness. But it should not be interpreted as a definite signal of drought or monsoon failure. Climate systems are interconnected and complex. El Niño increases the probability of below-normal monsoon conditions, but it does not determine the outcome alone. 

For India, the best approach is not panic—but preparedness. As the monsoon approaches, timely forecasts, adaptive planning, and climate-informed decisions will be essential across sectors. Because in India, the monsoon is not just a season. It is a system that connects climate, economy, and society.

Acknowledgment: 

I thank Tanu Sharma (PhD student) and Neha Rani (Scientific Assistant) at IMD Pune for helping me to generate some of these figures included in this post.

References:

Some of our relevant publications are listed here.


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