Overview
- Satellite altimeters and sea‑surface sensors including Sentinel‑6 and Sentinel‑3 have tracked eastward Kelvin waves and a broad band of warm water that raised sea levels near Peru by about 15 centimetres.
- The observation-based surge in tropical Pacific sea‑surface temperatures reported June 15 has led agencies and forecast ensembles to upgrade odds that El Niño will form and strengthen through late 2026.
- Many models now give roughly a two‑in‑three chance of strong‑to‑very‑strong El Niño conditions by the November–January peak, though forecasts still show spread and seasonal uncertainty.
- Forecasters warn the developing El Niño raises the risk of widespread marine heat waves, with high likelihood along the U.S. West Coast and Mexican Pacific and elevated risk in parts of the Indian and Southern Oceans.
- Scientists say continued satellite and in‑situ monitoring will refine peak strength and local impacts over the coming months, because El Niño typically peaks in November–January and regional outcomes remain uncertain.