If you've been following the weather and climate news lately, you've probably noticed one phrase appearing almost everywhere - Super El Niño. Forecasts from major climate centers including the World Meteorological Organization (WMO), National Oceanic and Atmospheric Administration (NOAA), Australia's Bureau of Meteorology (BOM), and the India Meteorological Department (IMD) increasingly point toward the development of a Super El Niño in 2026. Super El Niño is not the widely used term for an unusually strong El Niño Event. It generally represents conditions when sea surface temperatures in the equatorial Pacific Ocean rise to 2°C above the long term average. The emerging signal has already prompted concern across South Asia, where the summer monsoon remains the lifeline of agriculture, water resources, and hydropower production.
For Nepal, such headlines naturally attract attention. Nearly 80% of our annual rainfall arrives during the summer monsoon season. A weaker monsoon does not simply mean fewer rainy days. It can affect agricultural production, river flows, drinking water availability and even electricity generation.Historically, strong El Niño events have often coincided with below-normal monsoon rainfall across parts of South Asia, which is why meteorologists become cautious whenever the tropical Pacific starts warming this rapidly.
Source: Bureau of Meteorology
To understand why El Niño matters, we first need to look thousands of kilometers away from Nepal, into the tropical Pacific Ocean.
El Niño is one phase of a recurring broader climate system called El Niño Southern Oscillation (ENSO), which describes coupled interactions between the tropical Pacific Ocean and the atmosphere. ENSO has three phases: El Niño, when sea surface temperatures in the central and eastern tropical Pacific become warmer than average; La Niña, when they become cooler than average; and a neutral phase, when conditions remain close to average.
ENSO affects climate beyond the Pacific through teleconnections, altering large-scale circulation patterns influencing weather in distant regions including South Asia. Under normal conditions, strong trade winds blow from east to west along the equator, pushing warm ocean water toward Indonesia and Australia. This movement allows colder water to rise near the coast of South America through a process known as upwelling. Together, these oceanic and looped atmospheric circulation known as Walker Circulation, which maintain the normal distribution of rainfall across the tropics.
However, during El Niño, the normal Walker Circulation weakens. The trade winds lose strength, warm water spreads eastward across the Pacific, and the atmosphere begins to reorganize itself. Regions that normally experience vigorous thunderstorm activity can become quieter, while rainfall shifts into areas that are typically drier. Because the Pacific Ocean is such a dominant driver of global weather patterns, these changes influence atmospheric circulation patterns across the globe.
South Asia often feels the consequences. Research has shown that El Niño alters the Walker Circulation, the large-scale atmospheric circulation that spans the tropics. As convection shifts eastward into the Pacific, the atmosphere over parts of the Indian subcontinent tends to become less favorable for monsoon development. Ashok et al. (2004) demonstrated how strong ENSO events can reorganize tropical circulation patterns in a way that suppresses monsoon activity over South Asia. The result is often weaker monsoon winds, longer dry spells, and reduced seasonal rainfall.
Nepal has experienced these impacts before. Shrestha and Kostaschuk (2005) found that El Niño years are frequently associated with reduced streamflow across several major river basins in Nepal, particularly in western regions where rainfall is already comparatively lower. The relationship is not perfect and every El Niño behaves differently, but the overall signal is strong enough to warrant attention whenever a major event begins to develop.
However, while much of the focus remains on the Pacific Ocean, another climate driver is quietly evolving in the background. Forecasts suggest that the Indian Ocean Dipole (IOD) may shift into a positive phase during the same period. Unlike El Niño, which originates in the Pacific, the IOD describes temperature differences across the Indian Ocean. During a positive IOD, warmer than normal waters in the western Indian Ocean enhance evaporation and atmospheric convection there, while cooler waters near Indonesia reduce convection over the eastern Indian Ocean. This matters because the Indian Ocean also influences monsoon circulation. Several studies have shown that positive IOD events can sometimes counteract part of the drying influence associated with El Niño. Ashok et al. (2004) found that positive IOD conditions can modify circulation patterns and weaken some of the atmospheric mechanisms through which El Niño suppresses monsoon rainfall.
For Nepal, this interaction becomes even more interesting because our rainfall is not controlled solely by large-scale circulation patterns. The Himalayas fundamentally reshape the atmosphere. Moisture transported from the Bay of Bengal and, at times, the Arabian Sea is forced upward when it encounters the steep terrain of the Himalayan foothills. This process enhances cloud formation and precipitation. Wang and Gillies (2013) demonstrated that precipitation variability in Nepal does not always mirror broader monsoon indices used elsewhere in South Asia, highlighting the important role of regional geography and local circulation patterns.
Sigdel and Ikeda (2012) further noted that during El Niño years, a positive IOD may help maintain alternative moisture pathways into the region. The interaction between ENSO and IOD is not simply cancellation but both influence tropical atmospheric circulation simultaneously, but from different ocean basins. Their combined effects depend on relative strength, timing and interactions with the regional weather system.
It is also important to distinguish between seasonal rainfall totals and extreme rainfall events. A below-normal monsoon season does not necessarily eliminate the risk of floods. Even during El Niño years, individual monsoon depressions and favorable synoptic weather systems can generate episodes of intense rainfall capable of producing severe floods and landslides across Nepal. Seasonal climate outlooks therefore describe the probability of wetter or drier conditions over an entire season rather than predicting individual storms.
This is where the story becomes less straightforward than many headlines suggest. Current WMO seasonal outlooks indicate an increased probability of below-normal rainfall probabilities across much of the Indian subcontinent as El Niño strengthens. At the same time, forecasts also indicate the emergence of a positive IOD. In other words, the atmosphere appears to be receiving competing signals. One process generally favors a weaker monsoon. The other may provide at least partial support.
So can a developing positive IOD suppress the impacts of a Super El Niño on Nepal's monsoon?
Current evidence suggests that El Niño increases the likelihood of below normal monsoon rainfall across South Asia, while a developing positive IOD may partially weaken that influence. However, existing evidence doesn’t support confidently predicting either severe drought or near normal monsoon conditions in advance.
The Pacific Ocean is sending a strong warning signal, while the Indian Ocean may be providing a competing influence. The balance of current evidence therefore suggests an elevated risk of below-normal monsoon rainfall across Nepal and much of South Asia, but not a certainty. Ultimately, neither ENSO nor the IOD acts in isolation. Intraseasonal variability, Himalayan topography, and regional weather systems will together determine how Nepal's 2026 monsoon ultimately unfolds.
References
Ashok, K., Guan, Z., Saji, N. H., & Yamagata, T. (2004). Individual and combined influences of ENSO and the Indian Ocean Dipole on the Indian summer monsoon. Journal of Climate, 17(16), 3141-3155. https://doi.org/10.1175/1520-0442(2004)017%3C3141:IACIOE%3E2.0.CO;2
Neupane, N. (2008). To study the various factors affecting the summer monsoon rainfall in Nepal (Research report). Jackson School of Geosciences, The University of Texas at Austin.
Shrestha, A., & Kostaschuk, R. (2005). El Niño/Southern Oscillation-related variability in mean-monthly streamflow in Nepal. Journal of Hydrology, 308(1-4), 33-49. https://doi.org/10.1016/j.jhydrol.2004.10.020
Sigdel, M., & Ikeda, M. (2012). Seasonal contrast in precipitation mechanisms over Nepal deduced from relationship with the large-scale climate patterns. Nepal Journal of Science and Technology, 13(1), 115-123. https://doi.org/10.3126/njst.v13i1.7450
Wang, S.-Y., & Gillies, R. R. (2013). Influence of the Pacific quasi-decadal oscillation on the monsoon precipitation in Nepal. Climate Dynamics, 40, 95-107. https://doi.org/10.1007/s00382-012-1376-2
World Meteorological Organization. (2026, April 21). Global seasonal climate update for May-June-July 2026. https://wmo.int
World Meteorological Organization. (2026, May 21). Global seasonal climate update for June-July-August 2026. https://wmo.int
World Meteorological Organization. (2026, April 30). South Asia is expected to receive below average monsoon rainfall. https://wmo.int
National Oceanic and Atmospheric Administration Climate Prediction Center. (2026). Climate diagnostics bulletin: April 2026. U.S. Department of Commerce. https://www.cpc.ncep.noaa.gov
India Meteorological Department. (2026). https://mausam.imd.gov.in
Bureau of Meteorology. (2026). South Hemisphere Monitoring. https://www.bom.gov.au