El Niño could be one of the strongest on record — what it actually means for Ireland

News analysis · 26 September 2026. El Niño is already established and strengthening. Forecasts for its eventual peak are probabilistic, and a strong global El Niño does not translate directly into a specific Irish weather forecast.

A striking warning is circulating today: a “monster” El Niño could bring flooding, transport disruption and problems with food supply to Ireland.

There is a serious scientific story underneath the headline.

El Niño is strengthening rapidly in the tropical Pacific, and official forecasts say the event could become exceptionally powerful through late 2026 and early 2027.

But there is also an important Irish caveat:

Met Éireann says El Niño’s influence on Ireland and Europe is comparatively weak, highly variable and not robust in the present-day climate.

So the most accurate version of the story is not that El Niño is guaranteed to flood Irish towns or disrupt Irish transport.

It is that a potentially historic global climate event is developing at the same time as Irish seasonal models are signalling a wetter and milder-than-average end to the year — while global agriculture and food markets face a more direct El Niño risk.

How strong could this El Niño become?

Very strong.

NOAA’s Climate Prediction Center said on 10 September that El Niño was continuing to strengthen and that there was a greater than 90% chance of a very strong event during the Northern Hemisphere autumn and winter of 2026–27.

More strikingly, NOAA assigned a 75% chance that the October–December 2026 period would reach a level strong enough to exceed previous El Niño events in its record dating back to 1950.

That would mean a three-month Relative Oceanic Niño Index, or RONI, of +2.5°C or more.

The World Meteorological Organization has also said there is an exceptionally high — nearly 100% — likelihood that El Niño will persist through February 2027.

An experimental NOAA research model goes further. The September run of the GFDL SPEAR system found that all 30 ensemble members produced an event that would compete with, or potentially surpass, the strongest events in the historical record.

That last forecast is important, but it is experimental rather than NOAA’s official forecast.

The key distinction is this:

A historically strong El Niño is a forecast, not yet an observed final outcome.

What exactly is El Niño?

El Niño is the warm phase of the El Niño–Southern Oscillation, or ENSO.

It develops when unusually warm sea-surface temperatures across the central and eastern equatorial Pacific interact with the atmosphere and alter large-scale circulation patterns.

Because the tropical Pacific is enormous, those changes can affect rainfall, temperature, storms and drought risk thousands of kilometres away.

The effects are not the same everywhere.

Some regions become much wetter. Others become drier. Some experience stronger heat. Agricultural impacts depend on where crops are grown and when the altered rainfall arrives.

That is why a powerful El Niño can have major global consequences without producing one simple, predictable weather pattern in Ireland.

So what does El Niño usually mean for Ireland?

This is where the headline becomes less certain.

Met Éireann’s assessment is clear:

El Niño has strong and well-established effects in several parts of the world, but its influence on Ireland and Europe is comparatively weak and highly variable.

In other words, Ireland does not have a simple rule such as:

strong El Niño = wet Irish winter

or:

strong El Niño = widespread Irish flooding

The North Atlantic, the jet stream, surrounding sea temperatures, pressure patterns and other climate drivers all matter.

A very strong El Niño can influence the wider atmospheric system, but that does not mean every spell of Irish rain in the months ahead can be attributed to it.

Ireland is nevertheless heading into a wetter seasonal signal

Separately from the El Niño forecast, Met Éireann’s latest seasonal outlook for October, November and December 2026 currently points toward:

Indicator	Current seasonal signal for Ireland
Temperature	Above average overall
Mean temperature anomaly	Around 0.5°C to 1.0°C above normal
Rainfall	Likely to trend above average
Wettest signal	Strongest during November, especially in the south
Irish coastal sea temperatures	Around 0.2°C to 1.0°C above normal

That is worth paying attention to.

But Met Éireann also stresses that long-range forecasts have much lower skill than short-range forecasts and should not be used for specific planning in the same way as a 5- or 10-day forecast.

So it is reasonable to say that the coming months currently carry a wetter-than-average signal.

It is not reasonable to say today that a particular Irish town will flood because of El Niño.

Could transport be disrupted?

Yes — if severe Irish weather develops.

Heavy rain, flooding and high winds can obviously affect roads, rail, buses, ferries and flights.

But that is a consequence of the actual weather Ireland experiences, not a direct automatic consequence of the Pacific Ocean entering El Niño.

For households, commuters and businesses, the useful information will still come from:

• Met Éireann weather warnings;
• local flood alerts;
• Transport for Ireland and individual operators;
• ferry and airline updates;
• and short-range forecasts as individual weather systems approach.

A seasonal climate signal can tell us that the background odds may be shifting.

It cannot tell us whether the 08:10 train will run on a particular Tuesday in November.

Could El Niño push up food prices in Ireland?

This is where the global effect could matter more directly.

Ireland imports food, animal feed, ingredients and agricultural commodities from international markets.

The Food and Agriculture Organization says the developing 2026–27 El Niño is creating risks for crop and pasture production across parts of Africa, Asia, Central America and the Caribbean.

Its September food-price monitoring bulletin noted that global wheat, maize and rice prices rose in August amid weather concerns, strong demand and trade disruption, while El Niño was expected to continue into early 2027 and threaten production in several regions.

The FAO Food Price Index also rose 1.9% in August compared with July and 2.5% compared with a year earlier.

That does not mean El Niño alone caused those increases.

Food prices also move because of energy costs, exchange rates, wars, shipping, fertiliser prices, harvest sizes, trade restrictions and demand.

But if a very strong El Niño damages harvests in major producing regions, the effect can travel through international commodity markets — and ultimately into the price of some products bought in Ireland.

That indirect supply-chain route is more plausible than treating El Niño as a simple Irish weather switch.

And what about the “ugly potatoes”?

El Niño does not directly make Irish potatoes ugly.

Potato quality is affected by the actual conditions in the field: soil moisture, temperature, disease, timing of harvest and physical damage during lifting and storage.

Teagasc notes that harvesting potatoes in cold, wet soils can increase the number of diseased and rotten tubers.

This year has already shown why local conditions matter. In August, Teagasc reported significant pressure on Irish potato and vegetable growers after prolonged dry conditions and severe soil-moisture deficits.

So a wetter autumn could create a different set of problems from a dry summer.

But describing that as “El Niño potatoes” would skip several steps in the chain.

Could flooding become a bigger problem?

A wetter season naturally raises concern about saturated ground, rivers and surface-water flooding.

The current Met Éireann outlook gives above-average rainfall a meaningful probability during the final quarter of the year, with November carrying the strongest wet signal.

What it does not provide is a forecast of widespread flooding.

Flood risk depends on far more than the seasonal rainfall total:

• how quickly rain falls;
• whether repeated systems hit the same catchments;
• how saturated the ground already is;
• river levels;
• tides and coastal conditions;
• drainage capacity;
• and where individual storms track.

A month can finish wetter than average without producing a major flood disaster.

Equally, one intense rainfall event can cause serious local flooding even during an otherwise unremarkable month.

Is climate change making this worse?

El Niño is a natural climate cycle. Human-caused global warming is a separate long-term trend.

The two can occur at the same time.

WMO warns that a strong El Niño is now developing in a world that is already warmer, meaning the temporary warming influence of El Niño sits on top of a higher background temperature.

That combination can increase the chance of exceptionally high global temperatures and intensify some heat-related impacts.

Again, the Irish response is not necessarily the same as the global response. Met Éireann specifically cautions against assuming a strong direct El Niño effect on Irish temperatures.

What should people in Ireland actually do?

There is no reason for panic buying or trying to plan the winter around a single El Niño headline.

The practical response is much more ordinary:

1. Treat short-range Met Éireann forecasts as the main source for actual Irish weather.
2. Pay attention to rain and wind warnings when they are issued.
3. If you live in a flood-prone area, prepare for flooding because of your local risk — not because El Niño guarantees it.
4. Expect some volatility in global food and commodity markets if major agricultural regions are badly affected.
5. Do not assume every wet, warm or stormy spell in Ireland is “caused by El Niño”.

The bottom line

The developing El Niño is genuinely exceptional.

NOAA says there is a greater than 90% chance it becomes very strong, and a 75% chance that its October–December strength reaches a level beyond previous events in the record dating to 1950.

Globally, that increases the risk of major shifts in rainfall, drought, heat and agricultural production.

For Ireland, the conclusion needs more restraint.

Met Éireann says the direct El Niño signal here is weak and variable.

At the same time, Ireland’s current October–December seasonal outlook is pointing toward milder and wetter-than-average conditions, while global food markets are already watching El Niño-sensitive crops closely.

So flooding, travel disruption and food-price pressure are all plausible risks worth monitoring.

They are not predetermined outcomes of El Niño.