Why is this El Niño set to be so strong and what will its effects be in Ireland?

El Niño is a recurring climate event in which heat builds in the eastern equatorial Pacific before spreading through ocean and air currents. It typically occurs every two to seven years and lasts about a year, disrupting weather patterns around the world.

The name comes from South American fishermen, who observed that the phenomenon often peaked around December. They called it El Niño, Spanish for “little boy”, referring to the birth of Jesus.

El Niño can raise temperatures across much of the world and sharply alter rainfall. In some regions it brings prolonged drought; in others, severe flooding. Climate change did not cause the phenomenon, which was recorded long before climate change was identified, but the two can combine to produce more severe effects.

This event is expected to be particularly strong because ocean temperatures are exceptionally high, reaching 8 degrees above average in some places. Other natural shifts in winds and currents can affect how dominant El Niño becomes, but this episode is being driven by the unusual ocean heat.

In Europe, forecasts point to a hotter and wetter autumn and winter in the south, with colder and drier conditions in the north. Ireland’s position on the Atlantic makes forecasting more difficult, but Met Éireann’s analysis suggests wetter and milder conditions at least until late autumn and possibly through winter. That may appear relatively benign compared with conditions elsewhere, though recent nonstop rain already made farming difficult and caused severe flooding.

The event is expected to begin weakening from late spring 2027, but its heat and effects will take time to fade. A neutral period, known as Enso, could follow, or the climate could shift into La Niña, which has a cooling effect worldwide.