A developing El Niño in the tropical Pacific Ocean could become the strongest such event in living memory, according to the UK Met Office. The climate pattern is expected to intensify over the coming months, with forecasts indicating unusually high sea-surface temperatures across the Pacific. Scientists are monitoring the event because El Niño can influence temperatures, rainfall and weather patterns across large parts of the world.
El Niño is a naturally occurring climate phenomenon that develops when surface waters in the central and eastern tropical Pacific become warmer than average. It is part of the El Niño-Southern Oscillation, or ENSO, a climate pattern involving changes in ocean temperatures and atmospheric circulation. El Niño events generally occur every two to seven years and typically last between nine and 12 months.
The current event has already strengthened significantly. NOAA’s Climate Prediction Center reported that sea-surface temperature anomalies in the eastern equatorial Pacific exceeded 2°C in July. The Niño-3.4 region, which is widely used to monitor El Niño, recorded a temperature anomaly of 1.4°C, while the Niño-3 region reached 1.7°C and Niño-1+2 reached 2.9°C.
The Met Office expects the warming to continue. Its latest forecasts indicate that sea-surface temperature anomalies could exceed 3°C later this year as El Niño approaches its peak. Met Office long-range forecasting chief Adam Scaife described the projected event as unprecedented in the agency’s forecasting experience.
NOAA’s latest outlook also indicates an unusually high probability of extreme conditions. The agency gives a greater than 90% chance of a very strong El Niño during the Northern Hemisphere autumn and winter of 2026–27. It also estimates a 69% chance that the October-to-December period will produce an event exceeding the strength of El Niño episodes recorded since 1950, based on the Relative Oceanic Niño Index.
The effects of El Niño are global, although they vary by location. Changes in Pacific Ocean temperatures alter atmospheric circulation and can affect rainfall and temperature patterns in distant regions. Strong El Niño events have historically been associated with drought conditions in parts of Southeast Asia, Australia and southern Africa, while some areas of South America experience increased rainfall. Northwestern Europe can also experience wetter and stormier conditions during certain El Niño events.
Agriculture is another area affected by El Niño. Changes in rainfall and temperature can influence crops such as coffee, cocoa and sugar. Previous strong El Niño events have been linked to disruptions in agricultural production, demonstrating how changes in weather patterns can affect food markets and supply chains.
The potential temperature effect is particularly significant because El Niño occurs against a background of long-term human-caused global warming. El Niño itself is a natural climate phenomenon, but its warming influence can temporarily add to the existing rise in global temperatures. Many of the warmest years in the instrumental record have occurred during or shortly after El Niño events.
Scientists are therefore watching the event closely because of its potential influence on global temperatures in 2027. The Met Office has warned that the combination of a powerful El Niño and the existing warming trend makes it very likely that 2027 could become the hottest year on record. The exact strength and geographical effects of the event, however, will depend on how Pacific conditions develop over the coming months.
Although forecasts currently point toward an exceptionally strong El Niño, scientists emphasize that its final intensity cannot yet be known with certainty. NOAA notes that even a very strong El Niño does not guarantee particular weather conditions in every region. Its effects depend on the strength and location of Pacific warming as well as other atmospheric and oceanic factors.
The developing 2026–27 El Niño is consequently one of the most closely watched climate events of the year. If current forecasts are confirmed, it could rank among the strongest El Niño events observed in modern records and contribute to unusually high global temperatures in 2027.
