NOAA’s Climate Prediction Center puts the chance that the current El Niño reaches historic strength during October through December 2026 at 75%, which would make it stronger than any event on record since 1950. With a very strong El Niño now considered nearly certain, Americans should expect it to shape winter weather, heating demand, and farm conditions across the country.
Key Takeaways
- NOAA’s September 10 ENSO Diagnostic Discussion gives a greater than 90% chance of a “very strong” El Niño during fall and winter 2026–27.
- NOAA defines a historic-strength event as a three-month Relative Oceanic Niño Index (RONI) of +2.5°C (+4.5°F) or higher.
- NOAA’s September probability table keeps El Niño conditions at 100% through January–March 2027.
- The next ENSO Diagnostic Discussion is scheduled for October 8, the first update after the event’s expected peak period begins.
- NOAA’s August hurricane outlook gave a 75% chance of a below-normal Atlantic season, a pattern often linked to El Niño.
- The two strongest El Niño events on record, in 1997–98 and 2015–16, both brought heavy rain and flooding to parts of the southern U.S. and California.
How Forecasters Measure a Historic El Niño
El Niño forms when sea surface temperatures in the central and eastern tropical Pacific rise above normal for an extended period, changing atmospheric circulation around the world. NOAA tracks its strength using temperature anomalies in the Niño-3.4 region of the Pacific. More recently, it also uses the Relative Oceanic Niño Index, which adjusts for long-term warming of the oceans overall.
Under that relative measure, NOAA sets the historic threshold at +2.5°C sustained over three months. The 75% probability applies specifically to October through December 2026. The 2026 El Niño developed quickly over the summer, driven by a large store of heat below the ocean surface. By some conventional measures, July 2026 was already the warmest month in the Niño-3.4 record.
NOAA’s 75% figure describes the strength of El Niño itself, not the likelihood of any specific weather in any specific place. NOAA has said that stronger events make typical El Niño impacts more likely but do not guarantee them.
What a Strong El Niño Usually Means for U.S. Winters
El Niño tends to shift the Pacific jet stream south and strengthen it during the Northern Hemisphere winter. In past strong events, that produced a recognizable pattern across the United States.
The southern tier of the country, from California across the Southwest and Gulf Coast to Florida, has often been wetter and stormier than normal. During the 1997–98 El Niño, California and other parts of the southern U.S. had repeated storms, flooding, and landslides. Northern states, including the Pacific Northwest, northern Plains, and Ohio Valley, have often been milder and drier than normal. That can mean less snow in some mountain regions that depend on snowpack for water supplies.
These are tendencies, not forecasts. NOAA’s official U.S. Winter Outlook is expected later in October and will provide region-by-region temperature and precipitation probabilities based on the latest data.
Heating Costs Could Ease in the North
Winter temperatures largely determine how much households and businesses spend on heating. If El Niño brings a milder winter to the northern U.S., demand for natural gas, heating oil, and electricity could be lower than in a typical cold season. The U.S. Energy Information Administration usually publishes its Winter Fuels Outlook in October, and its weather assumptions will show how forecasters are factoring El Niño into price expectations.
Energy prices are already high this fall. AAA reported a September record average gasoline price of $4.33 a gallon, and diesel prices recently reached record highs. A milder winter would not reverse those increases, but it could reduce total heating costs for households in colder states.
Farmers and Water Managers Are Watching Closely
Agriculture is one of the areas most affected by a strong El Niño. Extra winter rain across the southern U.S. could improve soil moisture and reservoir levels in drought-prone areas, but heavy rain can also cause flooding and delay fieldwork. In the Pacific Northwest and northern Rockies, a lower snowpack could reduce water supplies for irrigation and hydropower next spring and summer.
Effects outside the U.S. matter too. The World Meteorological Organization has warned of higher risks of drought, heavy rain, and heat waves in many regions. Major producers in South America, Southeast Asia, and Australia often see crop disruptions during strong El Niño years, and those disruptions can affect U.S. grocery prices for imported goods such as coffee, cocoa, and some produce.
Flood and Coastal Risk in the Southern States
For homeowners and local officials in California, the Gulf Coast, and Florida, the main concern is heavy rain from repeated storms. After past strong El Niño events, federal, state, and local agencies stepped up flood preparation before winter. Clearing storm drains, checking flood insurance, and reviewing evacuation plans are routine steps emergency management agencies recommend in high-risk seasons.
The quieter Atlantic hurricane season linked to El Niño has been one benefit this year. Strong El Niño events tend to increase wind shear over the Atlantic, which can keep tropical storms from strengthening.
What Comes Next
NOAA’s October 8 ENSO Diagnostic Discussion will be the first official reading after the event enters its expected peak period, followed by the U.S. Winter Outlook. Together, they will show whether the 2026 El Niño is reaching historic strength and how it is likely to affect winter weather across the country.
FAQs
What Is NOAA’s Current El Niño Forecast?
NOAA’s September 10 update gives a greater than 90% chance of a very strong El Niño this fall and winter and a 75% chance of historic strength during October through December 2026.
What Does Historic-Strength El Niño Mean?
NOAA defines it as a three-month Relative Oceanic Niño Index of +2.5°C or higher, which would exceed every El Niño on record since 1950.
How Does El Niño Affect U.S. Winter Weather?
Strong El Niño winters often bring wetter conditions to the southern U.S. and California and milder, drier conditions to parts of the northern U.S. These are tendencies, not guarantees.
When Is the Next NOAA El Niño Update?
NOAA’s next ENSO Diagnostic Discussion is scheduled for October 8, 2026. The U.S. Winter Outlook is expected later in October.
How Long Will the 2026 El Niño Last?
NOAA’s September probabilities keep El Niño conditions in place through at least January–March 2027, before an expected weakening later in 2027.
