The United Nations weather agency forecast on Tuesday (June 2) a moderate or possibly strong El Nino that could drive up global temperatures and increase the risk of extreme weather over the coming months.

El Nino is a periodic warming of sea surface temperatures in the central and eastern Pacific Ocean, which typically lasts between nine and 12 months, according to the World Meteorological Organization.

The WMO said warm ocean waters were driving El Nino’s development and predicted above-average temperatures in most parts of the world from June to August. The WMO said it is likely El Nino will continue until November.

“A warmer ocean adds heat and moisture to the climate system, which can serve to worsen climate extremes, including heatwaves and heavy rainfall. The strong El Niño of 2023-2024 added a temporary warming effect on top of an already long-term warming trend," said WMO Secretary-General Celeste Saulo.

The weather pattern is known to disrupt regional climates, potentially bringing warmer temperatures across the globe, while increasing rainfall ⁠to southern South America, the southern United States, parts of the Horn of Africa and central Asia.

It can also cause drought ⁠in Australia, central America, Indonesia, and sections of southern Asia, and lead to the formation of hurricanes in the central and eastern Pacific Ocean, the WMO said.

The most recent El Nino, in 2023 to 2024, contributed to making 2024 the hottest year on record, Saulo added.

“Extreme heat alone is already one of the deadliest climate hazards we face, and an El Nino event could intensify the threat,” said Saulo. The risks include more heat-related illness, a wider spread of vector-borne diseases and increased pressure on food and water systems.

“Communities that were already struggling will be pushed farther beyond their limits,” she said.

A shift has been observed ⁠in the Equatorial Pacific, with sea surface temperatures rising rapidly from late April to mid-May, suggesting El Nino conditions were developing, the WMO said. The agency said it has observed unusually warm subsurface conditions across the tropical Pacific with temperatures exceeding 6 degrees Celsius above average, creating a reservoir of heat that is driving surface warming.

Some national weather agencies have forecast the strongest El Nino, in a decade, warning of hotter, drier weather across Asia in the second half of 2026 that is likely to damage crops and food supplies as farmers already struggle with fertiliser shortages and costly fuel caused by the Iran war. However, the WMO said currently there was still uncertainty about the strength of El Nino as some models are not predicting a strong El Nino.

While there is no evidence that climate change increases the frequency or intensity of El Nino patterns, it can make associated impacts such as extreme heatwaves and heavy rainfall worse, according to the WMO.

DESCRIPCIÓN DE IMÁGENES

SHOWS: GENEVA, SWITZERLAND (JUNE 2, 2026) (REUTERS - Access all)

1. VARIOUS OF WMO SECRETARY-GENERAL, CELESTE SAULO, ARRIVING AT PRESS CONFERENCE

2. PRESS CONFERENCE IN PROGRESS

3. (SOUNDBITE) (English) WMO SECRETARY-GENERAL CELESTE SAULO, SAYING:

“The World Meteorological Organization's latest El Niño-La Niña update confirms that El Niño conditions are developing in the tropical Pacific and are expected to influence weather and climate patterns around the world in the month ahead. Our experts estimate an 80% probability that El Niño conditions will emerge in the period between June and August 2026. This likelihood increases to around 90% through the remainder of the forecast period, that is September to December.”

4. PRESS CONFERENCE IN PROGRESS

5. (SOUNDBITE) (English) WMO SECRETARY-GENERAL, CELESTE SAULO, SAYING:

“A warmer ocean adds heat and moisture to the climate system, which can serve to worsen climate extremes, including heatwaves and heavy rainfall. The strong El Niño of 2023-2024 added a temporary warming effect on top of an already long-term warming trend. This contributed to 2024 becoming the hottest year on record.”

6. PRESS CONFERENCE IN PROGRESS

7. (SOUNDBITE) (English) WMO SECRETARY-GENERAL CELESTE SAULO, SAYING:

“In some regions, it is likely we will see heavy rainfall and floods. In others, drought conditions; in others, increased or reduced extreme heat or tropical cyclone activity. We can also expect an increased risk of extreme heat with higher temperatures and shifting precipitation patterns, adding further stress on human health, ecosystems, agriculture, and energy systems.”

8. PRESS CONFERENCE IN PROGRESS

9. (SOUNDBITE) (English) WMO SECRETARY-GENERAL CELESTE SAULO, SAYING:

“Extreme heat alone is already one of the deadliest climate hazards we face. An El Niño event could intensify the threat on average: more heat-related illness, wider spread of vector-borne diseases, increased pressure on food and water systems, and communities that were already struggling will be pushed farther beyond their limits.”

10. PRESS CONFERENCE ENDING

11. VARIOUS OF EXTERIORS OF THE U.N.