NOAA Puts the Odds of a Very Strong El Niño Above 90%, Raising the Stakes for 2027
US forecasters give a three-in-four chance the event will break the post-1950 record by late autumn, with its biggest effect on global temperatures expected next year.
US government forecasters now put the odds of a very strong El Niño this autumn and winter at better than nine in ten. The update, issued on Thursday by NOAA's Climate Prediction Center, also gives a 75% chance that the event will be the strongest recorded since 1950 by late this year. The implications reach from monsoon rains to global temperature records in 2027.
What the forecasters said
The centre kept its El Niño Advisory in place and said the event is still strengthening. The Niño-3.4 index, the patch of the equatorial Pacific used to measure El Niño, averaged 1.8°C above normal in August.
Its forecast gives a 75% probability that the index will exceed +2.5°C in October to December. That would place this event above every El Niño since reliable records in 1950 began, including the powerful episodes of 1997–98 and 2015–16.
The World Meteorological Organization reached a similar conclusion a week earlier. It said El Niño was almost certain to last through February 2027 and would probably reach very strong intensity by the end of this year, the first time it had issued such a clear-cut forecast. It reported temperatures below the ocean surface in parts of the Pacific more than 8°C above normal, a large reservoir of heat to sustain the event.
WMO Secretary-General Celeste Saulo warned it could deal "a massive blow to communities and economies across the world".
Why it matters
El Niño is a periodic warming of the tropical Pacific that shifts rainfall and wind patterns around the world. It does not cause climate change, but it adds a temporary boost of heat on top of long-term warming. That boost usually shows up most clearly in global temperatures in the year after an event peaks.
The timing is already concerning. Copernicus, the EU's climate service, reported this week that August 2026 tied July 2023 as the warmest month ever recorded, at 1.65°C above pre-industrial levels. Sea surface temperatures outside the polar regions reached a record for the month. A very strong El Niño peaking this winter would make 2027 a strong candidate for a new annual record.
Past strong events offer a guide to regional risks, although no two unfold the same way:
- Drought risk: historically higher in Indonesia, eastern Australia, southern Africa and parts of India.
- Flood risk: historically higher along the coasts of Peru and Ecuador and in parts of East Africa.
- Tropical storms: Atlantic hurricane activity tends to be suppressed, while the central and eastern Pacific becomes more active.
- Food and prices: harvest shortfalls in major producers can lift prices for rice, palm oil, sugar and cocoa.
Some of that pattern is already visible. The Atlantic hurricane season has been unusually quiet, while the North Pacific has produced a run of powerful storms, including Hurricane Lowell, which threatened Hawaii this week.
A complicating factor
El Niño does not act alone. The WMO noted that a positive Indian Ocean Dipole is developing, a separate pattern that can intensify drought in Australia and Indonesia while bringing heavier rain to East Africa. Conditions in the Atlantic will also shape how the event plays out in Europe and the Americas.
Outlook
For governments and aid agencies, the months before a peak are the window for preparation: pre-positioning food stocks, planning water rationing and issuing seasonal warnings to farmers. The UN's climate agenda will have to take account of it too, with COP31 opening in Antalya in November as the event is expected to reach its height.
NOAA's next assessment is due on 8 October.
Image: NOAA via Wikimedia Commons, Public domain