The UK is braced for what could be the hottest May day on record, with temperatures forecast to reach 33°C in south-east England on Sunday, surpassing the current high of 32.8°C set in 1922. According to the Met Office, thermometers are expected to hit 31°C on Saturday, 32°C on Sunday and 33°C on Monday over the Bank Holiday weekend. London is forecast to see 30°C on Friday, potentially outpacing popular holiday destinations such as Mykonos, Santorini and Ibiza. By Friday evening, temperatures had already climbed to 28.4°C in Cambridge, Heathrow and Cranwell.
Health alerts in place
In response to the prolonged hot spell, the UK Health Security Agency (UKHSA) has issued an amber heat health alert covering the East Midlands, West Midlands, East of England, London and the South East. Yellow alerts are active for the South West, North West, North East, and Yorkshire and the Humber. All alerts are in effect until 5pm on Wednesday, 27 May 2026. The warnings are part of the Heat-Health Alert service operated jointly by the UKHSA and the Met Office, which provides early warning to healthcare providers, social care organisations, voluntary groups and government departments about the potential health impacts of extreme temperature.
Since 2023, the system has moved to impact-based alerting, meaning the warnings now indicate not only the likelihood of hot weather but also the probable consequences for health and social services. The amber level — designated “Enhanced Response” — signals that impacts are likely to be felt across the whole health service, with the potential for the entire population to be at risk, and that non-health sectors may also observe effects requiring a coordinated response. The yellow “Response” level indicates that heat may affect particularly vulnerable people, prompting action from the health and social care sector.
Health risks and vulnerable groups
High temperatures can lead to dehydration, overheating, heat exhaustion and heatstroke, and can worsen pre-existing conditions such as respiratory and cardiovascular diseases. The UKHSA warns that older people — especially those over 75 — babies and very young children under five, pregnant individuals, and people with chronic illnesses including diabetes, kidney disease and dementia face heightened risk. Those with serious mental health conditions are also more vulnerable; heat stress can disrupt sleep, cause mood swings and exacerbate depression and anxiety. People who live alone, are homeless, have low socioeconomic status, are on certain medications, or have mobility problems are also at increased danger.
Historical heatwaves in the UK have demonstrated the deadly potential of extreme heat. The summer of 2003 saw a 42% increase in deaths in London, while approximately 3,000 excess deaths were recorded in England and Wales during the heat periods of summer 2022. That year marked the first time temperatures exceeded 40°C in the UK, with new national records set in England, Scotland and Wales. The UKHSA projects that, under a high-warming scenario, annual heat-related deaths could reach more than 21,000 by the 2070s.
The strain on healthcare is already evident. Overheating incidents at NHS sites in England have nearly doubled in the past five years, causing disruption to essential equipment, IT systems and services. The current heat event is expected to increase demand on health and social care, create challenges in managing medicines and maintaining safe temperatures in care settings.
Staying safe in the heat
Public health advice urges people to drink plenty of water and avoid alcohol and excessive caffeine. Carrying water when travelling is recommended, along with staying out of direct sunlight between 11am and 3pm when UV levels are highest. Lightweight, loose-fitting, light-coloured clothing and a wide-brimmed hat offer protection. Cool showers or baths, applying cool water to skin or clothes, and using cold packs on pulse points can help lower body temperature. Electric fans are effective only when the indoor temperature is below 35°C.
Keeping homes cool involves closing windows and curtains during the day — particularly on sun-facing rooms — and opening windows at night when temperatures drop. External shutters, awnings or planting shade-providing vegetation are longer-term measures. Physical exercise should be scheduled for the cooler parts of the day, such as early morning or evening. People are encouraged to check on friends, family and neighbours who may be vulnerable, ensuring they are aware of the forecasts and following advice. Public buildings such as libraries and places of worship can serve as cooling centres.
Broader impacts and policy context
Heatwaves also increase the risk of wildfires. During the 2022 heatwave, a 500% rise in 999 calls and 14 major wildfire incidents were reported as vegetation dried out. Climate change is expected to further raise the likelihood and severity of such fires. Workforce productivity suffers too, with two in five people reporting difficulty working in hot conditions. Transport systems and other infrastructure can be disrupted by extreme heat. Urban centres, particularly London, face additional risk due to the urban heat island effect.
The UK is warming at roughly 0.25°C per decade, and the last three years have been among the five warmest on record. Under a high emissions scenario, the UK could experience 40°C days every three to four years by 2100. Projections indicate that by 2050, heatwaves may exceed 40°C in all parts of the UK, with longer hot spells potentially leading to an additional 10,000 heat-related deaths annually. The Climate Change Committee has warned that the UK is unprepared, recommending that air conditioning be installed in care homes and hospitals within ten years, and in schools within 25 years. The government’s Adverse Weather and Health Plan, published in April 2023, replaced the previous Heatwave Plan for England and sits within the UK Government Resilience Framework, which aims to improve the nation’s ability to anticipate and respond to risks. There are also calls for a maximum working temperature to be set for both indoor and outdoor work.
