How Does La Niña Affect India’s Climate?

DIPAK KURMI

La Niña is often described as a distant oceanic phenomenon, unfolding thousands of kilometres away in the equatorial Pacific, yet its imprint on India’s climate is deep, persistent, and at times decisive. The term La Niña refers to the periodic cooling of sea surface temperatures across the central and eastern Pacific Ocean, particularly in the region stretching between Indonesia and South America. It is one phase of the larger El Niño Southern Oscillation, or ENSO, a coupled ocean–atmosphere system that plays a central role in shaping global weather patterns. Its counterpart, El Niño, represents the warming of the same oceanic region. Though these changes may appear subtle in numerical terms, they significantly alter atmospheric circulation, shifting winds, rainfall belts, and temperature regimes across continents, including the Indian subcontinent.

At present, La Niña occupies an uncertain but closely watched position in climate forecasts. The World Meteorological Organization has indicated that La Niña may develop in the coming three months, though the probability stands at only 55 percent. Earlier expectations that the phenomenon would emerge by July this year have not materialised, prompting a reassessment by meteorological agencies. The India Meteorological Department now anticipates that La Niña could set in by late 2024 or early 2025, a delay that may result in a relatively milder winter compared to a typical La Niña year. This uncertainty highlights the complexity of ENSO dynamics, where ocean temperatures, atmospheric pressure, and wind patterns interact in ways that resist precise prediction.

To understand how La Niña affects India’s climate, one must examine its physical mechanisms. La Niña occurs when air pressure at the surface over the equatorial Pacific is higher than normal, strengthening the trade winds that blow from east to west. These trade winds push warm surface waters further towards the western Pacific, near Indonesia, allowing colder waters from the ocean depths to rise near the coast of South America. This decline in sea surface temperature is not confined to the Pacific alone; it initiates a cascade of atmospheric responses that lower global average temperatures. As a result, many regions experience conditions that are cooler or wetter than usual, while others face droughts or intensified storms.

India’s relationship with La Niña is particularly significant during the monsoon season. Historically, La Niña years have been associated with normal or above-normal rainfall over much of the country. Stronger trade winds and cooler Pacific waters help reinforce the Walker Circulation, enhancing the flow of moisture-laden winds towards the Indian subcontinent. This often translates into a more robust southwest monsoon, vital for agriculture, water reservoirs, and overall economic stability. The La Niña years of 2020, 2021, and 2022 offer recent evidence, each delivering normal or above-normal rainfall across large parts of India. In contrast, the El Niño year of 2023 witnessed below-normal monsoon rainfall, reinforcing the long-observed inverse relationship between El Niño and Indian monsoon strength.

The historical record further deepens this contrast. Since 1871, India has received below-average rainfall during at least half of the El Niño years, underscoring the disruptive influence of warming Pacific waters on the monsoon system. Data also suggest an evolving pattern after 1980, with more intense El Niño events exerting uneven impacts across regions. Both north and south India have tended to receive less rainfall during strong El Niño episodes, while central India has remained relatively less affected. La Niña, on the other hand, promotes a more evenly distributed and vigorous monsoon, reducing the likelihood of widespread droughts. If La Niña forms now or early next year and persists through the monsoon season, it would likely mean less intense heat and more rainfall for India, offering respite after a period marked by extremes.

Temperature patterns during La Niña also reveal complex regional variations within India. La Niña is generally associated with colder conditions in the north-west and relatively warmer conditions in the south-east at a global scale. In India, this often translates into harsher winters, particularly across northern regions. However, the timing and maturity of the event matter greatly. This year, cities in south India such as Bengaluru and Hyderabad have experienced colder-than-normal winters, while north India has seen a delayed winter with above-normal temperatures. Some reports have attempted to link the southern chill to La Niña, but current Oceanic Niño Index values indicate the opposite. If La Niña had already developed, north India would have likely experienced colder-than-normal winters, suggesting that other atmospheric factors are currently at play.

Scientific analyses provide further nuance to this picture. A study of 35 years of meteorological data by researchers at the New Delhi-based Council on Energy, Environment and Water found that La Niña winters in India tend to have colder nights but warmer daytime temperatures compared to El Niño winters. The average wind speed is also higher throughout the day during La Niña winters, influencing thermal comfort, evaporation rates, and even air quality. These findings underscore that La Niña does not simply mean uniform cold, but rather a reshaping of daily and seasonal temperature cycles, with tangible implications for energy demand, agriculture, and public health.

Beyond rainfall and temperature, La Niña plays a critical role in cyclone formation and behaviour. During La Niña periods, intense hurricanes and cyclones are more likely to develop in the Atlantic Ocean and the Bay of Bengal. In the North Indian Ocean, including the Arabian Sea and the broader Indian Ocean, several supporting factors converge during La Niña years. Higher relative humidity, lower vertical wind shear, and favourable atmospheric instability create conditions conducive to severe cyclonic systems. The post-monsoon months from October to December are particularly significant, with November marking the peak period for cyclonic activity. A developing or mature La Niña during this window raises the risk of powerful storms affecting India’s eastern and western coastlines.

Globally, the impacts of La Niña illustrate the interconnectedness of Earth’s climate system. While India often benefits from stronger monsoons, other regions face adverse consequences. La Niña can cause excessive rainfall and flooding in Indonesia and surrounding areas, as well as in Australia, while Ecuador and Peru become drought-prone. Africa frequently experiences droughts during La Niña years, and hurricanes over the Atlantic tend to intensify. Conversely, El Niño brings extreme summers and droughts to India while increasing rainfall in the southern United States. These contrasting outcomes highlight that ENSO phases redistribute climatic risks rather than eliminating them, creating winners and losers across the globe.

The early years of this decade offer a striking example of ENSO variability. From 2020 to 2022, the world experienced three consecutive La Niña events, a rare phenomenon known as the Triple Dip La Niña. This sequence was followed by an El Niño in 2023, which contributed to intense, record-breaking heat waves in India, particularly in April. Such rapid oscillations between extremes raise concerns about the role of climate change in amplifying ENSO behaviour. Rising sea and land temperatures may be disrupting the delicate balance of the Pacific Ocean, increasing both the frequency and intensity of La Niña and El Niño events. There is growing evidence that extreme La Niña episodes could become more common, potentially leading to harsher winters and more volatile weather patterns in India.

Looking ahead, the potential arrival of La Niña carries both hope and caution for India. If it arrives and persists until the summer of 2025, it could bring relief from severe heat, moderate temperature extremes, and support a healthier monsoon. At the same time, it could heighten the risk of cyclones and regional flooding, particularly in coastal and low-lying areas. The delayed onset projected by the India Meteorological Department suggests a complex transition period, where winter conditions may remain milder even as atmospheric signals gradually shift. In this uncertainty lies a reminder that La Niña is not a single switch but a process, unfolding over months and interacting with local and global climate drivers.

Ultimately, La Niña’s influence on India’s climate is profound because it operates at the intersection of ocean physics, atmospheric dynamics, and regional geography. Its cooling breath from the Pacific shapes rainfall, temperature, winds, and storms across the subcontinent, often determining the difference between abundance and stress. As climate change accelerates and ENSO patterns grow more erratic, understanding La Niña is no longer a matter of academic interest alone. It is central to anticipating India’s climatic future, preparing for extremes, and adapting to a world where distant oceans increasingly dictate local realities.

(the writer can be reached at dipakkurmiglpltd@gmail.com)