A developing El Niño in the tropical Pacific could become very strong toward the end of 2026, and the WMO has warned that it could disrupt rainfall and temperature patterns in many parts of the world into 2027, raising risks of drought, flooding and extreme heat.
El Niño is the warm phase of a natural climate pattern in which sea-surface temperatures in the central and eastern equatorial Pacific rise above normal, shifting rainfall belts and storm tracks. Events occur every two to seven years and usually last nine to 12 months. El Niño is not caused by human-driven climate change, but it occurs on top of long-term warming, which can make heat impacts worse.
What the forecasts say
The WMO’s Oct 21 outlook projects a very strong El Niño for November 2026 to January 2027, with the sea-surface temperature anomaly in the Niño 3.4 region averaging about 3.8°C.
The US National Oceanic and Atmospheric Administration (NOAA) said on Oct 8 that a strong-to-very-strong El Niño is likely to continue through January to March 2027, with a probability of 83 percent or more. The Niño 3.4 index had reached +2.1°C. NOAA’s next update is scheduled for Nov 12.
The United Nations has warned that as many as 50 million people could face increased hunger linked to the event. The WMO outlook points to higher flood risk in parts of East Africa, drought in southern Africa and the Amazon, heat and wildfire risk in Southeast Asia, and wetter conditions in parts of North America.
South Asia and Nepal
A WMO assessment on Oct 14, based on the South Asian Climate Outlook Forum, forecasts normal to above-normal temperatures across most of South Asia for October to December. Below-normal rainfall is more likely over much of central and southern peninsular South Asia and parts of eastern South Asia, while normal to above-normal rainfall is expected in the northwest and some eastern and southern parts.
Nepal’s rainfall is shaped by the monsoon, winter weather systems from the west, elevation and Indian Ocean conditions as well as El Niño. The FEWS NET food security outlook for October to May assumes average winter and pre-monsoon rainfall in Nepal and rates the February to May 2027 forest-fire risk as below average.
Research by Small Earth Nepal, using more than four decades of data, found that Nepal’s summer monsoon tended to weaken in El Niño years, with about an 8 percent reduction in precipitation in its analysis. The strongest events in 1982, 1997 and 2015 showed sharper effects.
Agriculture and food
Wheat was the crop most affected in El Niño years. while rice and maize were more affected in La Niña years. A 2026 study of wheat varieties in the Terai found mean yield reductions of 67.4 percent under rain-fed conditions and 28.8 percent under heat stress compared with irrigated conditions.
The number of people needing food assistance in Nepal is expected that it could peak at 1.0 million to 1.49 million in December to January, as households in parts of central and western Nepal recover from flooding and high food prices. It expects winter planting to be below average in Rasuwa, Nuwakot and Dhading.
Water and electricity
The International Centre for Integrated Mountain Development (ICIMOD) reported in August that a survey of nearly 5,700 water sources in seven municipalities in Kavrepalanchok found 58 percent of active springs had declining flows, and more than a quarter had dried up. ICIMOD’s assessment of the 2025 Madhesh drought documented depleted groundwater, borehole failures and drinking-water shortages.
The Nepal Electricity Authority’s September dry-season plan estimates domestic generation at about 1,218 MW from mid-December to mid-May, with imports bringing total supply to about 2,373 MW. That is a planning estimate, not evidence that El Niño has reduced generation. A June study by the International Water Management Institute projected that dry-season output at the planned 900 MW Upper Karnali project could fall by up to 15 percent under long-term climate scenarios.
