El Niño Is Officially Here, and It May Become the Strongest This Century
The National Oceanic and Atmospheric Administration issued an El Niño Advisory on June 11, officially declaring that El Niño conditions have developed across the equatorial Pacific Ocean. The announcement, covered by Science AAAS and confirmed by multiple international meteorological agencies, marks the first El Niño in roughly two years, and potentially the strongest in the observational record.
“This event could rank among the largest in the historical record back to 1950,” NOAA’s Climate Prediction Center stated in its monthly outlook. Sea surface temperatures in the Niño 3.4 region, the benchmark zone stretching across the central equatorial Pacific, have risen more than 1°C above average, exceeding the +0.5°C threshold that defines El Niño. More concerning is what lurks below: a massive wave of anomalously warm water, more than 6°C above average in places, is creeping eastward at depth. This subsurface heat reservoir is the fuel that could drive an exceptional surface warming in the months ahead.
NOAA’s June outlook projects an 82% chance that El Niño will persist through the Northern Hemisphere fall, rising to 96% by the December-to-February window. The agency estimates a 63% chance that the event will reach “very strong” status, defined by an Oceanic Niño Index of +2.0°C or higher during the November-to-January peak. This probability has nearly doubled from 37% in the May outlook.
Multiple forecast models, including those from the ECMWF in Europe and the UK Met Office, are converging on a central estimate of roughly 2.7°C above average for the Niño 3.4 region by November, with a range from 1.8°C to 3.3°C. For comparison, the strongest events on record, 1982-83, 1997-98, and 2015-16, peaked between roughly 2.3°C and 2.6°C.
“Waters in the equatorial Pacific are warming sharply, and we’re very confident that there’s a big event coming,” said Prof. Adam Scaife of the UK Met Office. “It may even be a record event.”
The Atmospheric Connection
NOAA confirmed that the atmosphere has begun to respond to the warmer ocean, a critical transition that distinguishes a true El Niño from mere ocean warming. Trade winds across the equatorial Pacific have weakened, and convection patterns have shifted eastward. This coupling between ocean and atmosphere is what allows an El Niño to influence global weather patterns rather than remaining a localized Pacific phenomenon.
Michelle L’Heureux, who leads NOAA’s ENSO forecasting team, noted that the subsurface warmth “rivals some of the strongest El Niño events we have seen.” She cautioned that much depends on wind patterns over the coming months, which remain “the biggest wildcard” in intensity forecasts.
Expected Global Impacts
A very strong El Niño typically raises global average temperatures by roughly 0.2°C by transferring heat from the ocean to the atmosphere. On top of approximately 1.3°C of human-caused warming, this could push global temperatures to unprecedented levels, making 2027 the most likely candidate for the hottest year on record, since El Niño’s peak warming effect on global air temperatures lags by three to six months.
The typical teleconnection patterns for a strong El Niño include:
- Southern United States: Wetter than normal, with increased flood risk
- Southeast Asia and Australia: Hotter and drier, elevated drought and wildfire risk
- India: Weakened monsoon rainfall
- South America: Drier conditions in the Amazon and northeast; wetter in southern Brazil, Uruguay, and Argentina
- Greater Horn of Africa: Drier conditions in northern parts
- Atlantic hurricane season: Below-average activity expected due to increased vertical wind shear in the tropical Atlantic. Colorado State University’s June forecast projects only 11 named storms, 5 hurricanes, and 2 major hurricanes, roughly 40% below average.
Historical Context
The last El Niño, in 2023-24, was not especially strong, it never reached “very strong” classification. Even so, 2024 became the hottest year on record, driven primarily by background greenhouse gas warming. A much stronger event in 2026, layered on the same background warming, could produce impacts well beyond what previous El Niños have delivered.
“We’re already locked into a warmer world,” said Zeke Hausfather of Berkeley Earth. “A super El Niño in 2026 would be pouring fuel on the fire.”
Despite La Niña’s cooling influence through early 2026, 2025 still ranked as the third warmest year on record, hotter than the super El Niño year of 2016, illustrating how much the global climate system has warmed since the last very strong event.
UN Secretary-General António Guterres framed the event in urgent terms: “El Niño conditions will pour fuel on the fire of a warming world. Impacts will hit even harder, travel even farther, and cross borders with devastating speed.”
Sources: Richter, H. (2026). “El Niño has begun. It may become the strongest this century.” Science AAAS, June 11, 2026. NOAA Climate Prediction Center, June 2026 ENSO Outlook. Yale Climate Connections, June 11, 2026.