New Delhi: India is heading towards a deficient finish to its southwest monsoon as El Niño strengthens over the Pacific Ocean, with below normal rainfall expected in September and continuing risks of extreme weather.
The World Meteorological Organization said on September 3 that El Niño is firmly established and is expected to strengthen further, reaching very strong intensity in the coming months. The WMO said there is a nearly 100 percent likelihood that the event will persist through February 2027 and that it is expected to peak towards the end of 2026.
The development comes as India prepares for another month of below normal monsoon rainfall. The India Meteorological Department has forecast September rainfall at less than 91 percent of the long period average.
August rainfall across India was more than 16 percent below normal, according to the IMD. With September also expected to receive below normal rainfall, the IMD said the June to September monsoon season is most likely to end below 90 percent of its long period average.
The monsoon provides about 70 percent of India's annual rainfall and is important for agriculture and water supplies. Almost half of India's farmland lacks irrigation, making many farmers dependent on seasonal rainfall.
The rainfall deficit is raising concerns about crops such as cotton, soybean, corn and pulses, which are entering critical stages of development. Lower soil moisture could also create difficulties for winter crops such as wheat, chickpea and rapeseed.
The rainfall shortage is not evenly distributed across India. By the end of August, 312 of the 741 districts monitored by the IMD, or 42 percent, had received deficient rainfall. Another 38 districts, or 5 percent, had received large rainfall deficiency.
The southern peninsula recorded a rainfall deficit of more than 27 percent in August. Central India recorded a deficit of about 16 percent, as did eastern and northeastern India. Northwest India received about 10 percent less rainfall than normal.
Kerala illustrates why national rainfall figures do not tell the whole story.
The state received 1,367.1 millimetres of rainfall between June 1 and August 31, compared with a normal level of 1,746.8 millimetres. This represented a deficit of 22 percent.
At the same time, heavy rain in early August caused flooding and landslides in parts of Kerala, with 26 people reported killed by August 5.
The contrast between a seasonal rainfall deficit and destructive downpours is an important feature of the current weather situation. A deficient monsoon does not mean that every part of India will remain dry throughout the season.
Scientific research has found that El Niño can reduce India's overall summer monsoon rainfall while increasing the likelihood of extreme daily rainfall in particular regions. Research has identified this increased risk in parts of central and eastern India and along parts of the southwestern coast.
The effects are not the same across the country. Some regions can experience a reduction in extreme rainfall during El Niño years.
This means El Niño should not be treated as a simple explanation for every heavy rainfall event in India. The available evidence does not establish that El Niño directly caused the specific rainfall, floods or landslides in Kerala in August.
The Indian monsoon is influenced by several interacting climate systems. One of them is the Indian Ocean Dipole, which the WMO expects to enter a positive phase during the September to November period. The WMO has warned that conditions in other ocean regions can reinforce, weaken or alter the typical effects of El Niño.
The latest observations show how quickly the Pacific event has strengthened. The Niño 3.4 index, which measures sea surface temperature conditions in the central and eastern tropical Pacific, averaged about 1.5 degrees Celsius above normal from May to July and reached about 2 degrees above normal in July.
Weekly values later rose to between about 2.2 and 2.6 degrees Celsius above average. In some parts of the Pacific, temperatures below the ocean surface were more than 8 degrees Celsius above normal during July and early August.
The WMO classifies El Niño events as weak, moderate, strong or very strong. The term "super El Niño", sometimes used in media reports, is not an official WMO classification.
The current event is therefore more accurately described as a developing very strong El Niño.
For India, the immediate concern is the final phase of the southwest monsoon. The IMD has warned that rainfall activity over peninsular India is likely to remain subdued during the coming week.
Lower soil moisture and higher temperatures could affect agriculture if dry conditions continue. The impact will depend on how rainfall is distributed during the remaining weeks of the monsoon and how other regional climate conditions develop.
The strengthening El Niño is also expected to affect weather far beyond India. The WMO has warned of increased risks of major changes in rainfall and temperatures in different parts of the world, including drought, flooding and extreme heat.
For India, the immediate challenge is therefore a deficient monsoon combined with the continuing possibility of intense rainfall in some areas. As El Niño strengthens and is expected to continue into early 2027, its interaction with India's monsoon and other regional climate conditions will remain closely watched.