El Niño is firmly established and expected to strengthen into a very strong event before peaking towards the end of the year, with the World Meteorological Organisation (WMO) putting the likelihood of it persisting into early 2027 at almost 100%.
The South African Weather Service (SAWS) has warned South Africa to prepare for a hot and dry summer. Below-normal rainfall and above-normal temperatures over most of the country from October to December has been forecast.
The SAWS said the latest predictions indicated that the 2026/27 El Niño “will likely intensify further to become the strongest event in living memory”.
The WMO’s latest El Niño/La Niña Update puts the probability of El Niño continuing at nearly 100% during September to November 2026 and December 2026 to February 2027.
There is negligible probability of a return to neutral conditions and no indication of a transition to La Niña during the outlook period.
The confidence in the forecast is unusually high, driven by strong and mutually reinforcing signals in the ocean and atmosphere across the tropical Pacific, as well as close agreement among seasonal prediction systems.
The event is already showing exceptional ocean warming. The Niño 3.4 index, which measures sea surface temperatures in the central-eastern equatorial Pacific, averaged about 1.5°C above normal between May and July and 2°C above normal in July.
Weekly values climbed further between 29 July and 19 August, ranging from about 2.2°C to 2.6°C above average.
The heat is even more pronounced below the ocean surface. During July and early August, subsurface temperatures in parts of the central and eastern equatorial Pacific exceeded 8°C above average.
The WMO said the ocean conditions, together with atmospheric indicators including a strongly negative Southern Oscillation Index, confirmed that El Niño was firmly established and continuing to intensify.
A very strong El Niño increases the likelihood of significant changes in temperature and rainfall patterns in many parts of the world. But the WMO cautions that the strength of the event does not directly determine how severe its impacts will be in any particular country or region.
“Even during a very strong El Niño, impacts can vary substantially between regions and seasons,” the WMO said.
Other climate drivers, including conditions in the Indian and Atlantic oceans, can reinforce, weaken or modify the typical effects of El Niño.
The agency said El Niño was a natural climate phenomenon caused by interactions between the ocean and atmosphere in the tropical Pacific. It was not caused by climate change, although its effects were unfolding against a backdrop of global warming.
The SAWS said most El Niño events brought below-normal rainfall and above-normal temperatures to southern Africa, although not every El Niño produced drought. The 1997/98 very strong El Niño, for example, was associated with slightly above-normal rainfall over parts of South Africa’s summer rainfall region.
The latest SAWS seasonal forecast indicates that below-normal rainfall is the most likely outcome over most of South Africa from October to December, alongside above-normal temperatures. A similar outlook of drier and warmer conditions applies to November 2026 to January 2027.
The SAWS warned that the combination of the very strong El Niño and global warming could make 2027 the warmest year yet recorded.
It said the 2015/16 very strong El Niño brought unprecedented heatwaves to southern Africa and warned that, if the expected below-normal rainfall materialised, a high frequency of potentially severe heatwaves could occur.
The warning comes as the agriculture sector is also being urged to prepare.
In an El Niño advisory issued on Thursday, the department of agriculture said the country’s winter rainfall areas had experienced a shortage of rainfall, which could make the transition into the summer months challenging and require a focus on risk reduction.
“In the agricultural sector, El Niño conditions might result in below-normal rainfall and high temperatures that may lead to dry conditions and heat stress,” the department said. “This often contributes to crop failure and livestock mortality, especially where risk reduction measures are not implemented.”
The department said low rainfall could also trigger water restrictions, which usually affected irrigation farmers.
It urged farmers to implement risk-reduction measures, including avoiding unnecessary expansion of land under production and prioritising cultivars able to withstand dry and hot conditions. Pests and diseases associated with the conditions were also identified as a concern.