A strong El Niño is under way in the tropical Pacific. On October 8, 2026, NOAA’s Climate Prediction Center (CPC) issued an El Niño Advisory and said the event is still strengthening. Its synopsis reads that a strong-to-very strong El Niño is likely through January to March 2027. This article explains what the advisory says, what the numbers mean, and what it does and does not tell us.
What is El Niño?
El Niño is the warm phase of the El Niño-Southern Oscillation (ENSO), a natural pattern in which sea surface temperatures in the central and eastern tropical Pacific rise above average and the winds and rainfall that normally accompany the ocean change with them. Our entry on El Nino gives the background. The CPC issues a monthly diagnostic discussion that classifies the current state as neutral, El Niño or La Niña and issues an advisory when conditions are present.
How warm is the Pacific now?
The CPC gives September 2026 values for several regions of the equatorial Pacific.
- Niño-3.4 index: plus 2.1 degrees Celsius above average
- Niño-3 index: plus 3.0 degrees Celsius
- Niño-1+2 index: plus 3.9 degrees Celsius
Sea surface temperatures exceeded plus 4.0 degrees Celsius above average in parts of the eastern equatorial Pacific. The Niño-3.4 region is the one most often used to classify events, and the Niño-1+2 region lies closest to the South American coast. Subsurface temperatures were also well above average, which the CPC says indicates a deeper-than-average thermocline, the layer where ocean temperature changes rapidly with depth.
How strong could it get?
The CPC gives probabilities for how strong the event may become, measured by 3-month values of the Niño-3.4 index that reach at least plus 2.5 degrees Celsius on a relative basis.
- September to November: 54 percent
- October to December: 83 percent
- November to January: 70 percent
The official outlook expects El Niño to keep strengthening through the end of 2026. The document notes that a strong event raises the chance of El Niño-consistent impacts, though these are not guaranteed. The next CPC discussion is scheduled for November 12, 2026, which is the update to watch.
What is the atmosphere doing?
El Niño is a coupled ocean and atmosphere event, and the CPC describes both. Low-level westerly wind anomalies and upper-level easterly wind anomalies extended across the equatorial Pacific. Enhanced rainfall and convection shifted from the central to the eastern Pacific, while convection was suppressed over Indonesia. The Southern Oscillation indices, which track the pressure difference between the western and eastern Pacific, were significantly negative. These are the signs that tell forecasters the atmosphere is responding to the warm ocean and not just lagging behind it.
What do other agencies say?
The World Meteorological Organization (WMO) reported in September 2026 that El Niño is firmly established and is expected to intensify into a very strong event in the coming months. It said the event is likely to affect rainfall and temperature patterns into 2027, and that it influenced tropical cyclones, heavy rain, floods and drought. The Copernicus Climate Change Service (C3S) said El Niño conditions strengthened during September and that the monthly sea surface temperature in the Niño-3.4 region reached an all-time high for the month, above the peaks of 2015 and 2016. Our companion report on record global heat in 2026 covers the temperature picture.
Where are the effects felt?
The sources we used point to a few places and impacts. Suppressed convection over Indonesia fits the pattern in which dry conditions affect the western Pacific, and the Copernicus Atmosphere Monitoring Service reported that El Niño favored intensifying seasonal wildfires there. See our entry on Indonesia for background. The WMO also tied the event to heavy rain and flooding in some regions and to drought in others. Beyond those general statements, the CPC cautions that impacts are not guaranteed, so we do not list region-by-region forecasts. A strong event also raises the chance of bleaching on reefs, a link explored in our article on the fourth global coral bleaching event, although the sources used here do not make that connection themselves.
How to read the numbers
Three cautions apply. First, a probability is not a forecast of a single outcome, so 83 percent means that roughly one in six chances remain for a weaker result. That is our own arithmetic. Second, the index values describe ocean temperature, and impacts on land depend on season and location. Third, the next monthly discussion can change the picture, so this article reflects only the October 8 advisory.
Key figures at a glance
- Advisory status: El Niño Advisory, issued October 8, 2026
- Niño-3.4 index, September 2026: plus 2.1 degrees Celsius
- Peak sea surface anomaly: above plus 4.0 degrees Celsius in parts of the eastern Pacific
- Outlook: strong-to-very strong through January to March 2027
- Next update: November 12, 2026
Glossary: terms used here
- ENSO: the El Niño-Southern Oscillation, the Pacific pattern that alternates between El Niño, La Niña and neutral states
- Niño-3.4: a region of the central equatorial Pacific whose temperature is used to classify events
- Thermocline: the layer of ocean where temperature drops quickly with depth
- Anomaly: the difference from the long-term average
- Advisory: the CPC status issued when El Niño conditions are present and expected to continue
These definitions are general ones and are not quoted from the CPC document.
Frequently asked questions
Is El Niño happening now?
Yes. The CPC has an El Niño Advisory in effect and expects the event to keep strengthening through the end of 2026.
How strong will it be?
The CPC synopsis says a strong-to-very strong El Niño is likely through January to March 2027.
Does El Niño cause every extreme event?
No. The CPC says El Niño-consistent impacts become more likely in a strong event, but they are not guaranteed.
When is the next update?
The next CPC discussion is scheduled for November 12, 2026.