The summer of 2026 will be remembered not only for record-breaking temperatures, but also for the significant impact extreme heat had on ambulance services, patients and the wider urgent and emergency care system.
Following the hottest May on record, June became the second hottest June ever recorded, with temperatures approaching 38°C in parts of England. As temperatures rose, ambulance services saw a corresponding increase in demand, particularly for the most serious emergencies. National ambulance data shows a strong relationship between rising temperatures and increasing Category 1 and Category 2 incidents, with June recording the second-highest daily ambulance incident volume on record at more than 27,000 incidents per day. Category 1 incidents increased by 12% between April and June, while Category 2 demand also rose significantly compared with previous years.
The pressures were particularly evident across southern England. London Ambulance Service reported experiencing the busiest week in its history during the June heatwave, receiving more than 53,000 emergency calls and surpassing demand levels seen during the peak of the Covid-19 pandemic. The service attended more than 24,600 patients during the week and recorded its busiest-ever period for Category 1 incidents, including cardiac arrests and patients who had stopped breathing.
To help meet demand, additional ambulance crews were deployed across the capital and clinical hub capacity was expanded to support more patients remotely. Meanwhile, South Western Ambulance Service NHS Foundation Trust reported its busiest day on record during the May heatwave, with crews responding to almost 4,000 incidents in just 24 hours. Between the Bank Holiday Friday and Tuesday period, the trust responded to more than 18,200 incidents, an increase of more than 24% compared with the same period the previous year.
These examples reflected a broader national picture of sustained and exceptional pressure. Analysis published later in the year found that all ten English ambulance trusts experienced some of their busiest-ever days during the June heatwave, with several services recording unprecedented levels of life-threatening emergency demand and others reporting their highest-ever volumes of 999 calls.
The impact extended far beyond operational performance measures. Research by the Met Office, Imperial College London and the London School of Hygiene & Tropical Medicine estimated that around 2,700 excess deaths occurred across England and Wales during the May and June heatwaves. Ambulance clinicians and call handlers saw first-hand how quickly people could become seriously unwell, responding to increased numbers of patients suffering from dehydration, heat exhaustion, heatstroke, breathing difficulties and cardiovascular complications. The effects were often most severe among older people, those with existing health conditions and other vulnerable groups.
Evidence from elsewhere in the sector highlighted the nature of this demand. South Central Ambulance Service reported that the use of publicly accessible defibrillators more than doubled during periods of extreme heat, underlining the importance of community resilience and early intervention when responding to life-threatening emergencies such as cardiac arrest.
At the same time, hospitals were experiencing unprecedented pressure. June saw average daily A&E attendances exceed 81,000 across England, the highest level ever recorded. Increased ambulance demand combined with escalating emergency department activity inevitably affected patient flow across the wider urgent and emergency care system. More than 8,200 handovers exceeded 15 minutes each day in June, resulting in around 3,600 hours of lost ambulance time every day, equivalent to approximately 150 ambulance days lost daily while crews waited to transfer patients safely into hospital care.
For some services, the impacts continued long after temperatures subsided. Sustained heat-related demand created additional operational, workforce and recovery pressures. South Central Ambulance Service NHS Foundation Trust, for example, reported that increased emergency demand linked to prolonged periods of hot weather contributed to deteriorating response performance and the declaration of a critical incident during the summer. The trust subsequently developed recovery plans involving additional frontline ambulance capacity, highlighting the longer-term implications extreme weather can have for service resilience and resource planning.
Despite these challenges, ambulance services demonstrated remarkable resilience and adaptability. Nationally, Hear and Treat activity reached record levels, with more than 5,400 patients each day receiving assessment, advice and support without requiring a face-to-face response. Services increasingly used clinical hubs and alternative care pathways to ensure frontline resources remained available for the sickest patients. June became the highest month on record for Hear and Treat outcomes, highlighting the growing value of these approaches during periods of exceptional demand.
Throughout the summer, AACE and its members highlighted the risks posed by prolonged periods of extreme heat, particularly for vulnerable members of the public. Ambulance services consistently reported increased demand from people experiencing dehydration, heat exhaustion and heatstroke, alongside patients whose underlying cardiovascular and respiratory conditions were exacerbated by sustained high temperatures. The heatwaves reinforced how quickly patients can become seriously unwell and the importance of preventative measures, including staying hydrated, avoiding strenuous activity during the hottest parts of the day, checking on vulnerable friends and relatives, and making appropriate use of NHS services.
Reflecting on the summer’s experience, Anna Parry, AACE Managing Director, said:
This summer demonstrated both the growing impact that extreme weather can have on ambulance services and the remarkable resilience of our people. Despite unprecedented demand, staff and volunteers across the sector continued to deliver outstanding care for patients while adapting quickly to changing circumstances.
The learning from these events will be invaluable as we strengthen our preparedness for future periods of extreme weather.
Recognising the importance of capturing that learning, strategic ambulance service leads met on 21 October to hear from those ambulance services most adversely affected during the summer heatwaves, helping to inform planning and preparedness at both regional and national level. The event provided an opportunity to share operational experiences, identify emerging best practice and consider how services can continue to adapt to increasingly frequent periods of extreme weather.
While the summer heatwaves highlighted the vulnerability of the wider health and care system to prolonged periods of extreme heat, they also demonstrated the professionalism, adaptability and commitment of ambulance staff and volunteers across the UK. Through innovation, teamwork and an unwavering focus on patient care, services continued to deliver for patients during one of the most challenging summers in recent memory.
