FloodRadar
Log inCreate free account
Drag to turn the Earth
Sea surface warmer than the 1991–2020 average
Updated 13 September 2026 from NOAA’s 10 September discussion
El Niño 2026–27 is on course to be the strongest ever measured. This page explains what that is, how it works, where it is right now, and what it most likely means for rain, storms and rivers in the UK, and when.
El Niño lives in a strip of the Pacific along the equator wider than the whole Atlantic. Forecasters watch one rectangle of it above all, Niño 3.4, between 170° W and 120° W. In August 2026 its surface ran 1.8 °C warmer than the 1991–2020 average. Off the coast of Peru the water was 3.4 °C warmer than normal.
The glow on the globe is that warm water. It is not a shade of colour on a map: it is heat, enough to change where clouds form across a third of the planet.
Normally the trade winds blow steadily from east to west along the equator. They drag sun-warmed surface water towards Indonesia and pull cold water up from the deep off Peru. In an El Niño the trades falter. The warm water they were holding back sloshes east in slow waves that take two to three months to cross the ocean, and the rain that sits over the warmest water goes with it.
Drag the globe to follow the wind. The streaks are air; the faster they move, the brighter they are.
Move that much heat and rain and the atmosphere reroutes around it. The pattern repeats event after event: drought in Indonesia, Australia, India and southern Africa; floods in Peru and East Africa; a wet winter across the southern United States; a quiet Atlantic hurricane season. In 2026 the Indian monsoon has already run well below normal and the Atlantic had produced three named storms by late August.
Tap a marker on the globe, or read the list.
Britain sits at the far end of the chain. El Niño’s clearest effect here is on the jet stream, the river of fast air that steers Atlantic storms. In the first half of winter it tends to run stronger and point at the British Isles. That means named storms in quick succession, milder air, and rain on ground that never gets the chance to dry out.
Late in the winter the picture can flip. El Niño winters carry a somewhat higher chance of a weakened polar vortex, which opens the door to cold, blocked spells in January and February. The Met Office calls that link real but not strong.
The forecast models agree, and the Met Office says it has never seen an El Niño signal this intense. NOAA gives better than a 90% chance of a very strong event this winter and a 75% chance of a historic one. Met Office forecasts for Niño 3.4 run to more than 3 °C, beyond anything in the record since 1950. The World Meteorological Organization expects it to last until at least February 2027 and to peak around the turn of the year.
“We should be clear that this is an unprecedented event. I have never seen an El Niño signal this intense in our forecasts.”
A slice through the Pacific along the equator, Indonesia on the left, South America on the right. Switch between the three states and watch the wind, the warm water and the rain move.
In a normal year the trade winds blow west along the equator. Warm water piles up around Indonesia, where the sea stands about half a metre higher and the warm layer runs deep. Off Peru, cold water rises from below. Air rises over the warm pool and rains; it sinks over the cooler east and stays dry.
In an El Niño the trades weaken and sometimes reverse. Warm water spreads east along the equator, the cold upwelling off Peru shuts down and the warm layer flattens. The rising, raining air follows the warmth to the middle of the Pacific. Indonesia dries out; the Peruvian desert floods.
In a La Niña the opposite happens: stronger trades, a bigger warm pool in the west, colder water than normal in the east and heavier rain over Indonesia and Australia. The Pacific spent most of 2020 to 2023 in this state.
NOAA’s Climate Prediction Center keeps the score: an “El Niño Advisory” has been in force since 11 June 2026. These are its figures for August 2026, issued on 10 September 2026.
The standard yardstick. An event counts as very strong at +2.0.
Further east, already past the very-strong line.
The coast of Peru and Ecuador, where the anomaly is largest.
The western Pacific, barely warmer than normal: the heat is in the east.
What the Met Office, NOAA and the WMO have actually said, phase by phase, and what each phase tends to do to rivers.
Now to November 2026
The Met Office puts the chance of a warm and wet autumn at one-and-a-half to two times what it would normally be, with windier weather more likely later in the season.
Autumn rain lands on ground that dries out over summer, so early on it soaks in. Watch for the change: once soils are wet, every band of rain pushes rivers up faster and further.
How sure: Firm on El Niño, moderate on the UK
November 2026 to January 2027
The event is forecast to peak around the turn of the year. Historically this is when El Niño loads the Atlantic jet stream, and the Met Office already sees signals for increased rainfall and storminess in November and December.
Named storms in quick succession on saturated catchments is how Britain gets its worst river floods: December 2015 and October 2023 to January 2024 both happened in El Niño winters. Long, wet spells matter more than any single storm.
How sure: Firm on El Niño, moderate on the UK
January to February 2027
El Niño winters carry a somewhat higher chance of a weak polar vortex and a sudden stratospheric warming, which can bring colder, calmer spells to Britain late in the winter. The Met Office calls the link a real one but not a strong one.
Cold snaps pause river rises; the thaw that follows, especially with rain on snow, does the opposite. High groundwater after a wet autumn keeps chalk rivers and springs running high for months.
How sure: Lower
Spring and summer 2027
El Niño events usually decay through spring. The Met Office expects 2027 to become the warmest year on record and, for a time, more than 1.5 °C above the pre-industrial climate, with knock-on effects lasting through the year.
Whether spring floods follow depends on how wet the winter leaves the ground. The Easter 1998 floods came as that El Niño faded.
How sure: Lower
Every El Niño and La Niña since 1950. Warm seasons are orange, cool seasons blue. Choose an event to read what happened here and around the world.
1982–83
Very strong, peak +2.2 °C in Dec 1982 – Jan 1983
Britain barely noticed. The winter of 1982–83 was mild and mostly unremarkable here, a useful reminder that El Niño loads the dice for the UK rather than throwing them.
Catastrophic floods on the coasts of Peru and Ecuador, drought across eastern Australia that ended in the Ash Wednesday bushfires of February 1983, and a failed anchovy fishery. Forecasters had not seen it coming; the ocean-monitoring buoys that now stretch across the Pacific were built in its aftermath.
1997–98
Very strong, peak +2.4 °C in Nov 1997 – Jan 1998
A mild, damp winter with a record-warm February, then the Easter floods of 9–10 April 1998 as the event faded: a slow-moving band of rain sat over the Midlands, five people died and thousands of properties around Northampton, Leamington Spa and Evesham flooded.
Sea level off Peru stood higher than normal by tens of centimetres as warm water sloshed east. Torrential rain destroyed roads and bridges in northern Peru and Ecuador, forest fires and haze choked Indonesia, floods hit Kenya and Somalia, and worldwide losses ran to tens of billions of dollars.
2009–10
Moderate, peak +1.5 °C in Nov 2009 – Jan 2010
On 19 November 2009, 316 mm of rain fell at Seathwaite in Borrowdale in 24 hours, a UK record at the time, and Cockermouth and Workington flooded. Six weeks later the same El Niño winter turned bitterly cold: the coldest UK winter for three decades, with the whole island under snow on 7 January 2010. Wet early winter, cold late winter, in one season.
A moderate event by Pacific standards, but the northern winter of 2009–10 brought deep cold to Europe and the eastern United States while Canada had its warmest winter on record, the classic El Niño fingerprint on the northern hemisphere.
2015–16
Very strong, peak +2.6 °C in Nov 2015 – Jan 2016
Storm Desmond dropped 341 mm on Honister Pass in 24 hours on 5–6 December 2015, the UK record that still stands, and put Carlisle, Cockermouth, Keswick and Lancaster under water. Storm Eva brought the Boxing Day floods to Leeds, York and the Calder Valley; Storm Frank followed within the week. December 2015 was the wettest calendar month the UK had ever recorded.
The strongest El Niño since 1997–98. Fires and haze across Indonesia, drought in Ethiopia and southern Africa, mass coral bleaching on the Great Barrier Reef in early 2016, and 2016 became the warmest year then on record.
2023–24
Strong, peak +2.0 °C in Nov 2023 – Jan 2024
Storm Babet parked over eastern Scotland on 18–21 October 2023; red rain warnings were issued and Brechin was evacuated when the South Esk overtopped its defences. Ciarán followed in November, Henk flooded the Severn and Trent on 2 January 2024, and Isha and Jocelyn arrived within days of each other in late January. The 18 months to March 2024 were the wettest England has recorded. FloodRadar’s archive counts more flood alerts and warnings that winter than any other since 2006.
2023 became the warmest year on record and 2024 warmer still. The Amazon fell to record low levels, drought squeezed the Panama Canal, and southern Africa lost harvests to a failed rainy season.
2026–27
Forecast very strong to historic; +1.8 °C so far, for JJA 2026
The chapter that has not been written yet. Everything above is the pattern; what actually happens in Britain this winter will be decided by individual storms, weeks apart, on catchments that are either dry or already full. FloodRadar’s gauges, rain radar and alerts exist to tell you which.
Warnings in force now, rivers rising now, the next 24 hours.
El Niño is the largest natural swing in the world’s weather from one year to the next. These are three of its signatures.
Each bar is the number of flood alerts, warnings and severe warnings the Environment Agency raised in England between October and March, from FloodRadar’s archive. The colour is the state of the Pacific that winter.
In this archive, El Niño winters average about 4,120 alerts and warnings, La Niña winters about 2,740, and neutral winters about 4,170. 2 of the three busiest winters were El Niño winters. Read it as context rather than as a forecast: the number of areas that can be warned has grown over twenty years, and one wet fortnight can outweigh a whole season’s pattern.
Nothing on this page is fetched live. Each figure carries the date its source issued it, and the page is refreshed by hand after NOAA’s monthly discussion.
Save the gauges that matter to you, set a level alert, and let FloodRadar watch the river while you get on with your day.
FloodRadar helper · beta