Met Office Forecasts 28C as Late September Warm Spell Grips UK
The Met Office has confirmed that a late September warm spell could push temperatures to 28C across southern England, with forecasters warning of an extended period of unseasonably hot weather. According to the latest forecasts, the mercury could climb to 28C in parts of Berkshire and Wiltshire by Friday, September 25, while Somerset may reach 29C. The warm spell is expected to begin on Monday, September 21, and could last through the weekend, potentially meeting the Met Office's official heatwave criteria.
"There will also be some reasonably dry and more settled periods in between these systems, especially across southern areas," the Met Office stated in its forecast for September 19 to 28. "There is a chance settled weather may expand further northwards during the final week of September. Temperatures for the period as a whole will probably be close to average overall, but there is scope for some rather warm days at times, as well as relatively cool nights which may bring the occasional grass frost."
Regional Temperature Breakdown
Weather maps from WXCharts and Netweather show a horizontal band of 28C heat stretching across southern England, with the following areas expected to reach at least 27C:
- South West
- South East
- West Midlands
- East Midlands
- London
- Anglia
- Yorkshire/Humber
Specific counties reaching 28C include Dorset, Devon, Somerset, Hampshire, Wiltshire, Surrey, Kent, Essex, and Berkshire. By Friday, September 25, temperatures could peak at 29C in Somerset, South London, Surrey, and Cambridgeshire. The heat is not confined to the south; Greater Manchester may reach 24C, and parts of Yorkshire could hit 28C.
Met Office Heatwave Criteria and Current Forecast
A heatwave is officially defined by the Met Office as an extended period of hot weather where the daily maximum temperature meets or exceeds a specific local threshold for at least three consecutive days. For southern England, this benchmark sits between 26C and 28C during September. The upcoming warm spell, therefore, has the potential to be classified as a heatwave if temperatures consistently reach these levels.
Monday, September 21
Much of southern England will climb above 25C, with the South Coast—including Brighton and Bournemouth—forecast to be the warmest. Areas as far north as Yorkshire are anticipated to reach 24C.
Tuesday, September 22
Temperatures continue to rise, with Dorset, Berkshire, and Cambridgeshire reaching 26C.
Wednesday, September 23
Parts of Sussex also reach 26C as the warm spell persists.
Thursday, September 24
The heat intensifies, with highs of 27C in Somerset, Dorset, and Gloucestershire, alongside Berkshire. Cheshire reaches 25C.
Friday, September 25
The heat peaks with scorching highs of 29C in Dorset. The majority of the south reaches at least 27C, with other areas climbing to 28C.
Weekend, September 26–27
Saturday remains warm, with the hottest areas once again in the South West. Highs of 29C are expected on Sunday, with the majority of the nice weather hitting the south.
The Met Office's five-day forecast for the preceding week shows a mixed picture: "A cloudy start for many with showery outbreaks of rain. Bright spells developing at times through" the day. However, by Monday, warm and humid weather is expected to move towards the south, with showers across Scotland and Northern Ireland. Southern parts of England are forecast to stay mostly dry with sunny spells and temperatures climbing to 24C in London and 20C in Plymouth.
Context: Record-Breaking Summer and Ongoing Drought
The impending warm spell follows the UK's hottest summer since records began nearly 150 years ago. The Met Office confirmed that the mean average temperature across June, July, and August was 16.5C, beating the previous seasonal high of 16.1C set last year. Five separate heatwaves between May and August left the majority of the country in drought, sparked wildfires, and caused widespread travel disruption.
The highest temperature recorded this summer was on August 13 at Kew Gardens, when the mercury hit 38.1C. These extreme conditions have left soils dry and rivers depleted, meaning any additional heat could exacerbate existing water shortages and increase wildfire risks.
A Pattern of Late-Season Heat
This is not the first time September has delivered unusual warmth. In recent years, the UK has experienced several late-season heat spikes, a trend that meteorologists link to climate change. The Met Office has noted that further hot spells can be expected this month, consistent with projections for more frequent and intense heat events.
The Independent reported that summer-like temperatures are set to return early next week following a rainy start to September, with temperatures set to soar to 25C. The Met Office says warm weather and sunny spells are set to make a comeback this weekend, although heavy rain also features in the forecast. It's set to stay warm until Monday when temperatures could reach mid-20C in the south of England. But later in the week, cooler conditions are predicted to return.
"Changeable conditions with occasional rain or showers arriving from the North Atlantic are set to be frequent in northern and western parts of the UK until the end of September," the Met Office added. "But there will also be some dry and more settled periods in the south. Towards the end of September, high pressure may become more dominant bringing more settled conditions, with warmer daytime temperatures and cooler nights."
Perspective: Implications for Health, Environment, and Daily Life
If the forecast materialises, the late September heatwave could have significant implications. Public health officials may issue advice for vulnerable populations, while farmers and gardeners could face challenges from sudden temperature swings. The combination of dry soils and high temperatures also raises the risk of wildfires, particularly in southern and eastern regions.
Comparison to Recent Years
The summer of 2026 has already been exceptional. The previous record of 16.1C was set in 2025, and before that, the mean summer temperature had not exceeded 16C since records began. This rapid escalation suggests that the UK is warming faster than previously anticipated, with each successive summer breaking new records.
What This Means for the Coming Weeks
While the warm spell is notable, it is not unprecedented for September to deliver temperatures in the high 20s. However, the length and intensity of this event could rival some of the most significant late-season heatwaves on record. The Met Office's caution about "relatively cool nights" is also important: even during warm spells, nighttime temperatures can drop sharply, potentially leading to grass frost in rural areas.
As the UK prepares for this final blast of summer heat, residents are advised to stay hydrated, avoid prolonged sun exposure during peak hours, and keep an eye on local forecasts. The Met Office will continue to monitor the situation and update its guidance as necessary.
For those planning outdoor activities, the weekend of September 26–27 looks particularly promising, with widespread sunshine and highs approaching 29C. However, the warmth is expected to be short-lived, as cooler, more autumnal conditions are likely to return by the end of the month.
In the meantime, the unseasonable warmth serves as a reminder of the changing climate and the need for adaptive strategies to cope with increasingly frequent extreme weather events.
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