Revealed: June 2026 heatwave in England caused record demand for ambulances

All ambulance services in England experienced some of their busiest days during this summer’s record June heatwave, according to data obtained by Carbon Brief.

In June, temperatures surpassed 37°C in some parts of the country as authorities declared only the second “red” warning for extreme heat.

Four in 10 NHS ambulance services, including London, responded to a record number of life-threatening emergencies on at least one day, from June 23 to 27.

Two other services, in the south west and east of the country, received the highest volume of 999 calls on record.

Ambulance services have provided data on their busiest days since records began, in response to freedom of information (FOI) requests from Carbon Brief.

The results show how demand during the June heatwave exceeded levels seen during the traditionally busy winter season of other years (and even at the height of the Covid-19 pandemic) for many services.

Heat demand

Extreme heat increases the risk of numerous life-threatening conditions, including heart disease and respiratory problems.

England experienced record temperatures in late June, and the entire country was covered by amber or red “heat health alerts” from the government.

A red alert, issued for the entire midlands and south of England, indicates “a significant risk to life even for the healthy population.” This was only the second time such an alert was triggered.

Researchers estimated there were almost 3,000 heat-related deaths in the UK this summer. There has also been unprecedented demand for emergency departments and some ambulance services.

To investigate the strain ambulances face, Carbon Brief sent data requests to all 10 NHS ambulance trusts in England, asking for lists of their busiest days.

This covered both the total volume of 999 calls and “category 1” responses, referring to incidents involving “life-threatening injuries and illnesses” such as heart attacks.

The graph below shows the busiest days recorded for ambulances in England, including total calls and category 1 responses. Most services were able to provide records dating back to the 2010s. (See: Methodology).

The five-day period between June 23 and June 27 is overrepresented in these results, with at least two heat wave days in the top 20 for all services in the country.

This trend is especially pronounced in the south and east of England, where June temperatures exceeded 36°C and even approached 38°C in some regions.

Ambulance services in London, the south east coast, the south central and the north east reported daily records for responding to life-threatening emergencies during the heatwave.

For the South East Coast and South Central services, covering a region stretching from Oxfordshire to Kent, a record number of category 1 calls were recorded on 25, 26 and 27 June.

Services in the south west and east of England recorded record numbers of 999 calls on June 26, the same day the highest temperature ever recorded in the UK in June was reported in Norfolk.

It is worth noting that demand for ambulance services – including category 1 calls – has been growing for many years, driven by factors such as an aging population, more complex health conditions and increasing pressures on mental health.

This helps explain why dates before the 2020s are rare in the main rankings provided to Carbon Brief.

Beyond the heat wave, 2026 as a whole is on track to be a record year for ambulance demand.

“Stifling heat”

June 26, On the busiest day of the heatwave, ambulances across England attended 4,084 life-threatening emergencies.

The average daily volume of this type of incident is usually around 2,500 during the summer months.

Stu Holliday, head of preparedness, resilience and emergency response at North East Ambulance Service, tells Carbon Brief:

“During periods of warm weather, we typically see an increase in calls from people affected by dehydration, heat exhaustion and heat stroke, as well as those whose existing health conditions, particularly heart and respiratory illnesses, may be worsened by prolonged high temperatures.

“Older people, young children and pregnant women may be especially vulnerable.”

Ambulance crews are generally busier in winter because cold weather and seasonal illnesses increase the number of serious medical emergencies.

However, June data shows that extremely hot days are starting to equal or even surpass cold ones as busiest days. This is a trend seen throughout the healthcare system.

While not all services provided records until 2019, the data broadly shows that ambulances were busier during the heatwave than at the height of the Covid-19 pandemic.

In addition to patients, heat waves put pressure on ambulance workers. Union UNISON has warned that crews are facing “stifling heat with faulty or no air conditioning” and “back-to-back call-outs” due to increased demand.

Methodology

Carbon Brief requested data on the 50 busiest days for England’s top 10 ambulance services.

These are: London; Southeast Coast; South Center; Southwest; West Midlands; East Midlands; East of England; Northeast; Yorkshire; and Northwest.

Data was requested from service records. Most were able to provide records dating back to sometime in the 2010s, with the exception of Northeast and South Central, which only had records from 2021 and 2022 onwards, respectively.

Rising annual demand for ambulance services means that most of the busiest days for ambulances have been in the 2020s. For example, all but four of the busiest days for category 1 emergencies reported to Carbon Brief were in the 2020s.

Carbon Brief requested data on ambulance demand for all UK countries. In Scotland and Northern Ireland, where temperatures are colder, services did not see call volumes reach the top 50 rankings during the June heatwave. The Welsh Ambulance Service did not respond to Carbon Brief’s request.