Warm water, record territory
The El Nino that formed in the Pacific this year keeps getting stronger. In its September update, NOAA's Climate Prediction Center said there is a greater than 90% chance of a very strong event during the northern hemisphere autumn and winter of 2026-27.
Sea surface temperatures in the eastern equatorial Pacific are running more than 3C above average, with the key Nino-3.4 index at plus 1.8C. The centre also reported that the subsurface ocean remains warmer than normal, which gives the event room to grow.
NOAA puts the odds at about 75% that this El Nino will end up stronger than any since 1950, the earliest year with usable records. European seasonal models project the peak could reach levels never seen in the instrument record.
What it means for weather
El Nino shifts where storms form and how they track. The World Meteorological Organization expects above-normal temperatures across almost all land areas from September to November, with rainfall patterns showing a classic response to a strong Pacific event.
The US winter outlook leans warmer than normal across the northern tier and wetter than normal from the southern plains toward the East Coast. Forecasters warn that a warm winter does not rule out snow. It changes where storms form and how long cold air lasts.
Other regions face the opposite risk. Southern Africa, parts of Central America and northern Australia are more likely to see dry conditions, which is already prompting water and crop warnings in several countries.
Climate talks in a hot year
The outlook lands during Climate Week NYC, which runs from September 20 to 27 and brings governments, investors and companies together in New York. The past year has brought deadly floods and debris flows in the Himalayas, wildfires and extreme heat across Europe, and record ocean warmth.
Some climate outcomes are getting easier to measure. Researchers reported this month that heat waves now start earlier in the season and build faster than they did 45 years ago, a shift that stretches emergency planning and public health systems.
Scientists also caution that a strong El Nino adds heat on top of the long-term warming trend, which means 2027 is likely to rank among the hottest years on record. That combination keeps pressure on governments to pair adaptation spending with cuts to greenhouse gas emissions.