Britain is on the brink of its first significant heatwave of the year, with weather experts and meteorologists predicting a spell of unusually warm conditions set to sweep across the country in late May 2026. After a sluggish start to the month marked by a cold snap, wind, and rain, the UK is poised for a dramatic turnaround, with temperatures expected to soar well above seasonal averages in many regions. According to the Met Office, the nation could be just weeks away from seeing the mercury climb past 30°C, a threshold rarely crossed outside of high summer.
The Met Office’s latest three-month outlook, covering May through July, offers a 40 percent chance of a “hot” summer, consistent with the UK’s recent trend toward warmer weather. As reported by multiple outlets, including the Express and GB News, meteorologists say that the first true heatwave could arrive as soon as the week of May 17 to May 26, 2026. During this period, high pressure is forecast to build from the south, ushering in a run of dry, settled, and increasingly warm weather—especially in southern England.
Jim Dale, a meteorologist with British Weather Services, told GB News, “I would expect that by the time we get to July and August, we could be back in the territory where there is a fair chance of seeing another 40C. If there is a heatwave over Spain and the Continent, all it would need is a push northwards for us to tap into these very high temperatures, and it is entirely possible we could reach or hit the record. This is going to make things very interesting as we go through summer, particularly when it comes to heat and humidity.”
Before those record-breaking highs become a real possibility, the UK is preparing for a notable surge in temperatures later this month. Weather maps from WXCharts, cited by the Express, show that as many as 17 regions—including London, Hertfordshire, Essex, Suffolk, Cheshire, Manchester, and even Grampian in Scotland—are expected to bask in temperatures climbing to 27°C or more. Remarkably, this would make parts of the UK warmer than Greece, where the hottest region is forecast to reach 25°C during the same period.
On Friday, May 22, much of England, Scotland, and Wales will surpass 20°C, with the capital expected to hit 27°C just before the weekend. The warmth will be felt across the south, with Hertfordshire, Essex, and Suffolk all forecast to reach 25°C. Further north, Cheshire and Manchester are likely to enjoy highs of 23°C, and even the North East of Scotland could see temperatures around 22°C. The Met Office’s long-range forecast for May 17 to May 26 predicts that while conditions will start off cooler and unsettled, temperatures will “tend to recover as the period progresses, perhaps becoming rather warm by the end of the period, especially in the south.”
The heat isn’t limited to southern England. According to WXCharts data, cities like Birmingham, Bristol, Cardiff, Manchester, Oxford, Brighton, and Cambridge are all expected to experience highs up to 26°C during the three-day spell from May 22 to May 24. On May 23, Greater London, Somerset, Kent, West Sussex, East Sussex, Leicestershire, Gloucestershire, and Warwickshire are all forecast to reach 26°C. By Sunday, May 24, temperatures are set to peak again in Greater London, the South East, South West, and the West Midlands, with some northern areas and parts of Scotland, like Aberdeenshire, remaining unseasonably warm for late May.
The European Centre for Medium-Range Weather Forecasts (ECMWF) model, as highlighted in the Daily Express, supports these predictions, showing temperatures could climb as high as 27°C in the southeast and 26°C in the Midlands on May 23. The model also suggests that 18 counties—including Yorkshire, Nottinghamshire, Derbyshire, Leicestershire, Staffordshire, Gloucestershire, Herefordshire, Shropshire, Warwickshire, Cambridgeshire, Oxfordshire, Somerset, Dorset, Berkshire, Surrey, Hampshire, Buckinghamshire, and Monmouthshire in Wales—could see highs of 25°C or above during this four-day warm spell.
But what does it take for the UK to officially declare a heatwave? The Met Office defines a heatwave as a period when temperatures meet or exceed the regional heatwave threshold for three consecutive days. These thresholds range from 25°C in northern regions to 28°C in the southeast. With forecasts suggesting that many areas will hover around or above these marks, the coming spell could well be classified as a heatwave, particularly in the south where the threshold is highest.
The timing of this warm spell couldn’t be better for families, as it coincides with the school May half-term holidays across England and Wales. After a May that began with the coldest night in five years and plenty of unsettled weather, the prospect of sunshine and warmth is a welcome change. The Met Office’s forecast for May 17 to May 26 reads, “As this period progresses, high pressure is likely to begin to build from the south bringing more in the way of settled weather. Temperatures likely cooler than average to begin, but tending to recover as the period progresses, perhaps becoming rather warm by the end of the period, especially in the south.”
Of course, not all experts agree on just how hot things will get. While some forecasts are optimistic about the possibility of 30°C or even higher, others suggest that realistic highs for the coming spell are closer to 27°C, with the increased risk of even warmer weather the further south you go. The Met Office remains cautious, noting that “consistent with our warming climate, the next three months are more likely to be warm than cool. An increased chance of warm conditions implies a greater-than-normal chance of heatwaves, similar to that in recent years.”
One factor influencing the UK’s weather pattern this year is the likely development of El Niño in early summer. According to AccuWeather meteorologist Paul Pastelok, “The sea surface temperatures are quickly changing in the equatorial Pacific, so fast that this El Niño could begin in June. Tremendous warming of sub-surface water temperatures across the central and eastern Pacific.” While El Niño’s effect on the UK in early summer is typically small, it does increase the chances of unsettled weather, adding another layer of unpredictability to the forecast.
Still, the overall picture is clear: as May draws to a close, Britain is heading into a period of much-anticipated warmth, with the potential for the first official heatwave of the summer. Whether or not the country reaches the 30°C mark this month, the consensus among meteorologists is that a hot summer is on the cards—and after a chilly start to the season, most Britons will be more than ready to soak up the sun.
With forecasters keeping a close eye on the developing patterns and the public eagerly awaiting relief from the spring chill, the coming weeks promise to be both meteorologically intriguing and, for many, a welcome taste of summer.