El Ni帽o brings more intense rain to India's wettest regions
Paul Arnold
contributing writer
Gaby Clark
scientific editor
Robert Egan
associate editor
A new study has made a counterintuitive discovery about how El Ni帽o affects India's summer monsoon. Instead of reducing rainfall overall and causing widespread droughts, the periodic climatic phenomenon increases rainfall daily in the country's wettest regions.
El Ni帽o, which means little boy in Spanish, is a complex, cyclical weather pattern that warms the surface waters in the eastern Pacific Ocean. This weakens trade winds and alters atmospheric conditions, a process that has long been known to suppress summer rainfall in India. However, most previous studies focused on average rainfall over an entire season. This new research, in the journal Science, specifically examined extreme daily rain during El Ni帽o years to reach its surprising conclusion.
To understand the connection between Indian rainfall and El Ni帽o, the researchers took a deep dive into more than a century's worth of data. They analyzed daily rainfall records from India's Meteorological Department (1901鈥�2020) and used specialized statistical tools to measure the frequency and intensity of extreme rainfall events. Finally, to examine the physical conditions, they cross-referenced this with atmospheric data from 1979 to 2020.
The study found a direct connection between Indian rainfall and El Ni帽o. In the drier regions of southeastern and northwestern India, this climate phenomenon reduces total rainfall and the intensity of extreme events. However, in the wet central and southwestern parts of the country, it results in less frequent but more intense downpours. This is due to changes in convective buoyancy, an atmospheric force that powers storms.
During El Ni帽o summers, convective buoyancy increases in the wettest regions, which makes more extreme rainfall likely. The chance of a very heavy downpour (more than 250 mm of rain) increases by 43% across all of India's monsoon-affected areas and 59% for the Central Monsoon Zone during El Ni帽o summers.
"Extreme daily rainfall over the Indian summer monsoon's rainiest areas becomes more likely the stronger that El Ni帽o conditions are," commented the researchers in their study.
Better predictions
These deluges can have devastating consequences, with flooding inundating villages, sweeping away homes and causing major economic hardship. That makes this research all the more vital because authorities and farmers need to better prepare for these dangerous events.
"This raises the prospect of skillful ENSO-based (El Ni帽o鈥揝outhern Oscillation) seasonal forecasts of extreme rainfall probabilities within monsoonal India," added the research team.
With more accurate forecasts that take into account El Ni帽o patterns, the world's most populous country can better mitigate flood risks and protect lives and livelihoods.
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More information: Spencer A. Hill, More extreme Indian monsoon rainfall in El Ni帽o summers, Science (2025). .
Journal information: Science
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