Japan’s Meteorological Agency said Friday that El Nino conditions, present in the equatorial Pacific since spring, are certain to persist through the Northern Hemisphere autumn, a signal that already-elevated global temperatures could climb further this year and into 2027.
El Nino is a periodic warming of surface waters in the eastern and central Pacific that alters weather patterns worldwide. The agency’s monitoring showed sea surface temperatures in the NINO.3 region — a benchmark stretch of the equatorial Pacific — running 1.2 degrees Celsius above normal in May, with warm water continuing to propagate eastward beneath the surface and trade winds weakening across the central Pacific. Those conditions, the agency said, will keep pushing surface temperatures higher through the fall.
The U.S. Climate Prediction Center has reached a similar conclusion independently, maintaining an El Nino advisory and forecasting a 97% chance the event persists through early 2027 while continuing to strengthen. The two agencies differ slightly in their timelines but agree on the trajectory: an El Nino that emerged this spring is not expected to fade before next year.
The current event moved quickly through forecasters’ watch lists. In April, Japan’s agency had described conditions in the tropical Pacific as neutral; by May it put the odds of El Nino developing by summer at 90%. Early last month, it became the first major weather agency to declare the phenomenon officially underway, days ahead of a similar assessment from the World Meteorological Organization. The U.S. Climate Prediction Center had put the odds of El Nino emerging in June at 82% around the same time.
The World Meteorological Organization warned last month that the event could grow strong enough to rival some of the most powerful El Nino episodes on record. “We need to prepare for a potentially strong El Nino event, which will exacerbate drought and heavy rainfall and increase the risk of heatwaves both on land and in the ocean,” WMO Secretary-General Celeste Saulo said.
The last comparable event, in 2023 and 2024, ranked among the five strongest on record and contributed to consecutive years of record global heat, with 2024 ultimately surpassing 2023 as the hottest year measured. Zeke Hausfather, a scientist at the climate research group Berkeley Earth, has said a strong El Nino this time around could meaningfully raise the odds that 2027 becomes the hottest year yet recorded.
Regional forecasters are already adjusting seasonal outlooks around the event. The Greater Horn of Africa Climate Outlook Forum has projected a high likelihood of below-normal rainfall across the region’s northern areas during the June-to-September rainy season, and South Asian forecasters expect this year’s monsoon to bring below-average rainfall. The Philippines’ state weather bureau, PAGASA, has said El Nino conditions are likely to persist into the September-to-November period at moderate to strong intensity, with a chance of a still-stronger event forming by early 2027.
El Nino’s effects on tropical cyclones typically cut in opposite directions across ocean basins: warm water in the central and eastern Pacific tends to fuel hurricane activity there, while stronger wind shear over the tropical Atlantic tends to suppress it. U.S. forecasters have cited that pattern in projecting a below-normal Atlantic hurricane season this year.
Within Japan, the agency’s seasonal outlook points to above-normal temperatures nationwide in the months ahead, consistent with the pattern typically observed in Japan during past El Nino events. Scientists caution that El Nino is not solely responsible for the extraordinary ocean warmth recorded over the past two years, pointing instead to a longer-term trend of human-caused warming that oceans have absorbed in large part as heat.
Coral reefs and marine ecosystems already strained by successive years of ocean heatwaves face renewed pressure as the event develops, scientists tracking the phenomenon have said. The European Union’s Copernicus climate monitoring service reported that April ranked as the third-hottest such month on record globally, with temperatures running 1.43 degrees Celsius above pre-industrial levels, while Arctic sea ice extent stayed near record lows for the month.
Some forecasters have drawn comparisons to the 1997-98 El Nino, at times described as a “super” event and among the most disruptive of the past half-century, though officials caution it remains too early to say how the current episode’s peak strength will compare.
The Japan Meteorological Agency’s next assessment of the event is due in early August.
