An "unprecedented" El Nino could bring wetter and stormier conditions to the UK this autumn and winter.
The Met Office has warned that the natural weather event, which warms sea temperatures in the tropical eastern Pacific by at least 0.5C above average, is expected to become the most significant since the 19th century.
Temperatures could exceed 3C in the coming months.
Professor Adam Scaife, head of long-range forecasting at the Met Office, said: "We should be clear that this is an unprecedented event.
Staying safe during a thunderstorm
"I have never seen an El Nino signal this intense in our forecasts."
He added: "A typical El Nino leads to an equatorial Pacific sea-surface temperature rise of between one to 2C, with 2C being a really big event.
"This implies that if the forecast is accurate – and other forecast systems show similar extreme values – then 2026 will far exceed our recent experience of El Nino and its worldwide climate influences."
El Nino events can influence weather across the globe, increasing the risk of drought in the tropics, southern Africa and north-east Australia, while bringing wetter and stormier conditions to north-western Europe, including the UK.
They also drive up global average temperatures, with 2027 expected to become the hottest year on record.
Dr Nick Dunstone, Met Office science fellow, said: "During large El Nino events significantly more heat is released from the ocean to the atmosphere leading to an increase in global average temperature, particularly in the calendar year following the winter peak of the El Nino.
"Hence, 2027 is very likely to replace 2024 as the warmest year on record and be another year to temporarily exceed plus 1.5C above the pre-industrial period."
Professor Stephen Belcher, chief of science and technology at the Met Office, said: "This summer we have experienced heatwaves across Europe reminding us of the effects of climate change, this large El Nino is a reminder that natural variations in the climate system are also at play, adding to the stresses of climate change."
Some showers could be heavy and thundery today and tomorrow. Take care when travelling, as even moderate rain can reduce your ability to see and be seen.
Take a look at some of our tips and advice to stay #WeatherReady ⤵️ https://t.co/5j5aH5J25E— Met Office (@metoffice) August 20, 2026
The UK has already faced extreme weather in recent months, with July recorded as the driest in 190 years.
Nearly three-quarters (71.3%) of England and all of Wales have been classified as being in drought.
Reservoir levels have dropped to 62.6%, which is 16.3% lower than is expected for this time of year, according to Defra.
Following an emergency meeting to discuss the heatwave last week, Prime Minister Andy Burnham warned: "We might be in for a wet autumn and winter straight after this, because of El Nino and some of the issues there, which was reported to Cobra."
Recent heavy rain has provided some relief, with Morecambe in Lancashire recording 52.5mm in 24 hours.
This represents a third of the region’s rainfall totals recorded over the period between June 1 and August 18 this year, which reached up to 156mm on average.
What different Met Office weather warnings mean
Pevensey Bay in East Sussex saw 32mm in the same period.
However, forecasters and officials have cautioned that it will take months of sustained rainfall to fully replenish rivers, reservoirs and groundwater.
The National Drought Group, which includes water companies, regulators, farmers and scientists, said this week’s rainfall and cooler temperatures would not significantly improve the water shortage.
Drought conditions could persist into the new year, as current forecasts don't suggest enough autumn rainfall to support recovery before December.
The panel is now meeting weekly to coordinate its response to the ongoing crisis, amid increasingly volatile weather driven by climate change.
You may notice a chillier start during Friday morning 🥶
Generally a dry start for many, though some showers remain in places 🌦️
Feeling fresh in the northerly breeze 🌬️ pic.twitter.com/OjNB9b5pjK— Met Office (@metoffice) August 20, 2026
Earlier this month, the UK experienced its fifth heatwave of the year, with temperatures hitting 38.1C at Kew Gardens, London on August 13.
August 14 was provisionally the 10th day in 2026 where temperatures exceeded 35C or more.
Recommended reading:
- UK Government bans sale of disposable barbecues after sparking wildfires
- Full list of retailers where disposable barbecues are banned from sale
- What to do if a dog is in a car on a hot day and can you smash a window to get it out
2026 is the first year on record with three separate days where temperatures reached the 37C threshold.
Wildfires have also broken out, including in Stourbridge in the West Midlands, where 19 homes were destroyed.
The National Fire Chiefs Council reported 1,132 wildfires across England and Wales so far in 2026 – a record high for this point in the year.
Are you ready for the cooler seasons? Let us know in the comments below.
Share