Official Statistics

Heat mortality monitoring report, England: 2024

Published 3 April 2025

Applies to England

The annual heat mortality monitoring reports have been published as official statistics for the first time, demonstrating that they are produced in line with the standards of trustworthiness, quality and value in the Code of Practice for Statistics.

These statistics include, for the first time, observed deaths broken down by place of death, cause of death and local resilience forum (LRF). Previous reports for 2016 to 2023 were published by the UK Health Security Agency (UKHSA) and Public Health England.

Main points

• there were 1,311 (95% confidence interval [CI]: 929 to 1,692) heat-associated deaths during the 4 heat episodes in the summer of 2024

• there were 282 more heat-associated deaths than predicted, based on the observed temperatures in summer 2024 and the historic temperature-mortality relationship in England

• the highest heat-associated mortality rates were seen in those aged 85 years and over (521 per million population), and those aged 75 to 84 years (111 per million population); there were 2,844 and 4,087 heat-associated years of life lost, respectively, in these age groups

• higher heat-associated deaths were seen in the heat episodes earlier in the summer than those later on in the season

• significant heat-associated deaths were seen in 3 out of the 4 heat episodes of the summer, despite only yellow heat-health alerts (HHAs) being issued

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Heat episodes

A heat episode is defined as an amber HHA in at least one region, or when the mean Central England Temperature (CET) is at least 20 degrees Celsius (°C). One day either side is also included. Note that in the case of the first episode in 2024, an additional day was included at the start of the episode. See data sources and methodology for more information.

There were 4 heat episodes which met this definition in 2024, comprising a total of 14 days. This is the fourth lowest number of heat episode days since UKHSA statistics began in 2016. These will be labelled episode 1 (E1) to episode 4 (E4) for the remainder of this report.

Episode 1 (E1)

The first heat episode lasted 4 days (24 June to 27 June 2024), during which no amber HHAs were issued. However, a yellow HHA was issued for the North West, Yorkshire and The Humber, East Midlands, West Midlands, East of England, London, South East and South West, lasting from 24 June to 27 June. Mean CET reached 20°C.

Episode 2 (E2)

The second heat episode lasted 3 days (18 July to 20 July 2024), during which no amber HHAs were issued. However, a yellow HHA was issued for the East Midlands, West Midlands, East of England, London, South East and South West, lasting from 18 July to 20 July. Mean CET reached 20°C.

Episode 3 (E3)

The third heat episode lasted 4 days (30 July to 2 August 2024), during which no amber HHAs were issued. However, a yellow HHA was issued for Yorkshire and The Humber, East Midlands, West Midlands, East of England, London, South East and South West, lasting from 29 July to 1 August. The yellow HHA was extended to 2 August in East Midlands, East of England, London and South East. Mean CET reached 20°C.

Episode 4 (E4)

The fourth heat episode lasted 3 days (11 August to 13 August 2024), during which no amber HHAs were issued. However, a yellow HHA was issued for the North West, Yorkshire and The Humber, East Midlands, West Midlands, East of England, London, South East and South West, lasting from 11 August to 13 August. Mean CET reached 20°C.

Observed heat-associated mortality

Overall findings

There were an estimated 1,311 (95% CI: 929 to 1,692) deaths associated with the 4 heat episodes during summer 2024. See our data sources and methodology section for information on how this number is calculated.

Figure 1 shows daily deaths and daily mean CET across the summer period, with grey shading indicating the 4 heat episodes. Increases in deaths above the baseline (shown by the turquoise line) can be observed for each heat episode. There is additional variation within the daily deaths series that is not associated with heat episodes. There is also a general trend of higher mortality at the beginning and the end of the season than in the middle of the summer.

Figure 1. Daily deaths and daily mean temperature, England, summer 2024

E1 had the second highest mortality of 394 (95% CI: 184 to 603) heat-associated deaths, with on average 98 (95% CI: 46 to 151) heat-associated deaths per heat episode day. There was significant mortality in those aged 85 years and over and those aged 75 to 84 years; in females and in males; and in care homes and hospitals. The highest number of daily deaths during summer 2024 was seen on the first day of E1.

E2 had the highest mortality of 467 (95% CI: 288 to 646) heat-associated deaths, with on average 156 (95% CI: 96 to 215) heat-associated deaths per heat episode day. There was significant mortality in those aged 85 years and over and those aged 75 to 84 years; in the North West, South East and South West regions; in females and in males; and in own homes, care homes and hospitals.

E3 had the third highest mortality of 275 (95% CI: 72 to 477) heat-associated deaths, with on average 69 (95% CI: 18 to 119) heat-associated deaths per heat episode day. There was significant mortality in those aged 85 years and over; in the West Midlands region; and in hospitals and care homes.

E4 had an estimated 142 (95% CI: -28 to 312) heat-associated deaths, which was not statistically significant. There was significant mortality in those aged 85 years and over (115 [95% CI: 7 to 224] deaths), and in care homes (90 [95% CI: 8 to 171] deaths).

Table 1 in the accompanying spreadsheet shows heat-associated deaths and heat-associated deaths per day by heat episode. Tables 2, 4, 5 and 6 show breakdowns by heat episode and region, age group, sex and place of death, respectively.

Observed mortality by region and heat episode

The South East had the highest number of heat-associated deaths over the summer of 259 (95% CI: 104 to 414). Significant heat-associated mortality was also seen in the North West, West Midlands, East of England, London, South East and South West. Differences between these regions were not statistically significant.

Regions were affected differently across the heat episodes (Figure 2). Heat-associated deaths peaked in E1 in London and the South West, in E2 in the North West and South East, and in E3 in the West Midlands and East of England. Notably, the North West region saw significant heat-associated deaths in E2 (71 [95% CI: 2 to 140] deaths) despite not having any HHA issued for that period.

Figure 2. Heat-associated mortality rate by region and heat episode, England, summer 2024

Note: error bars represent 95% confidence intervals.

The West Midlands had the highest mortality rate of 38 (95% CI: 17 to 59) heat-associated deaths per million population.

Table 2 in the accompanying spreadsheet shows heat-associated deaths and mortality rates by region and heat episode.

Observed mortality by local resilience forum area

For the first time in UKHSA’s annual heat mortality monitoring reports heat-associated mortality was analysed for smaller geographic areas than regions, at the level of LRFs. LRFs are multi-agency partnerships made up of representatives from local public services, including the emergency services, local authorities, the NHS and the Environment Agency. They bring together emergency planning and response arrangements for incidents and emergencies, including adverse weather events such as heatwaves.

In 2024, the following LRFs saw statistically significant heat-associated deaths over the summer: London, West Midlands, and Kent. Almost all other LRFs had estimates of heat-associated deaths greater than zero, but these were not statistically significant due to the wide 95% CIs when considering smaller population groups.

Adjusting for population size, the highest rate of heat-associated mortality was seen in Cleveland LRF in the North East (72 [95% CI: -1 to 145] per million population), although this was not statistically significant.

Figure 3 shows heat-associated mortality per million population at LRF level. The first map in Figure 3 shows rates for all LRFs regardless of statistical significance, while the second map only shows rates for LRFs where there were statistically significant heat-associated deaths.

Figure 3. Heat-associated mortality rate in all LRFs (first map) and LRFs with statistically significant heat-associated deaths (second map), England, summer 2024.

Table 3 in the accompanying spreadsheet shows heat-associated deaths and mortality rates by LRF.

Observed mortality by age group and heat episode

Significant heat-associated mortality was seen in those aged 85 years and over and those aged 75 to 84 years. Those aged 85 years and over had the highest number of heat-associated deaths with 753 (95% CI: 511 to 996). This was a rate of 521 (95% CI: 353 to 688) per million population. There was no significant heat-associated mortality in 2024 in younger age groups.

Figure 4. Heat-associated mortality rate by age group and heat episode, England, summer 2024

Note: error bars represent 95% confidence intervals.

Table 4 in the accompanying spreadsheet shows heat-associated deaths and mortality rates by age group and heat episode.

Observed mortality by sex and heat episode

Heat-associated mortality was analysed according to sex as recorded on death certificates. Significant heat-associated deaths were seen in females (684 [95% CI: 417 to 952] deaths) and males (627 [95% CI: 355 to 899] deaths). The estimate for females is higher, but not significantly different from the estimate for males. It is not possible to report on heat-associated deaths for unknown or other sexes due to small numbers.

Figure 5. Heat-associated mortality rate by sex and heat episode, England, summer 2024

Note: error bars represent 95% confidence intervals.

Table 5 in the accompanying spreadsheet shows heat-associated deaths and mortality rates by sex and heat episode.

Observed mortality by place of death and heat episode

For the first time in UKHSA’s annual heat mortality monitoring reports, heat-associated mortality was analysed according to place of death as recorded on death certificates. See our Quality and Methodology Information (QMI) report for a description of the methodology for grouping places of death.

There was significant heat-associated mortality across the summer for those who died:

• in care homes (496 [95% CI: 315 to 677] deaths), which saw significant deaths in all 4 heat episodes

• in hospitals (473 [95% CI: 230 to 716] deaths), which saw significant deaths in the first 3 heat episodes, and the highest number in E1

• at their own residence (358 [95% CI: 153 to 563] deaths), which saw significant deaths particularly in E2

There was no significant heat-associated mortality for those who died in hospices or in other places.

Figure 6. Heat-associated deaths by place of death and heat episode, England, summer 2024

Note: error bars represent 95% confidence intervals.

Care homes saw the largest percentage increase in mortality in heat episodes compared to the baseline, of 13% (95% CI: 8% to 18%).

Table 6 in the accompanying spreadsheet shows heat-associated deaths and percentages above baseline by place of death and heat episode.

Observed mortality by cause of death

For the first time in UKHSA’s annual heat mortality monitoring reports, heat-associated mortality was analysed according to underlying cause of death. See our QMI report for a description of the methodology for grouping causes of death.

The leading cause for heat-associated mortality was ‘All circulatory diseases’, with 440 (95% CI: 251 to 629) heat-associated deaths. This represented a percentage increase of 11% (95% CI: 6% to 15%) above baseline deaths. This was followed by ‘Dementia and Alzheimer’s’, with 229 (95% CI: 96 to 362) heat-associated deaths. This was an increase of 11% (95% CI: 5% to 18%) above baseline deaths. Cardiovascular diseases and neurological diseases have been identified in academic research as risk factors for heat-associated mortality (Adverse Weather and Health Plan: supporting evidence document).

Significant heat-associated deaths were also seen for deaths caused by influenza and pneumonia, with 79 (95% CI: 7 to 150) deaths. Heat-associated deaths were not significant for cancer, chronic lower respiratory diseases or external causes. The result for external causes should be interpreted with caution, due to the additional registration delays for deaths reported to coroners, including sudden, violent and unnatural deaths.

Figure 7. Heat-associated deaths by cause of death, England, summer 2024

Note 1: error bars represent 95% confidence intervals. Note 2: the figure for ‘external causes’ should be interpreted with caution due to additional registration delays

Table 7 in the accompanying spreadsheet shows heat-associated deaths and percentages above baseline by cause of death.

Observed heat-associated years of life lost

Years of life lost (YLL) is a measure of premature mortality, which takes into account remaining life expectancy at age of death. Heat-associated YLL for summer 2024 has been calculated based on the distribution of heat-associated deaths across those aged 75 to 84 years, and those aged 85 years and over. It is not calculated for younger age groups as they did not see statistically significant heat-associated mortality in summer 2024.

While those aged 85 years and over had the highest number of heat-associated deaths across summer 2024, the highest heat-associated YLL was found in those aged 75 to 84 years with 4,087 (95% CI: 2,091 to 6,083).

Figure 8. Heat-associated years of life lost by age group and heat episode, England, summer 2024

Note: error bars represent 95% confidence intervals.

Table 8 in the accompanying spreadsheet shows heat-associated years of life lost by age group and heat episode.

Comparison with modelled mortality

As well as calculating observed mortality, a statistical model was used to estimate predicted mortality in each heat episode in 2024. This was based on the historic temperature-mortality associations in England and the actual temperatures observed in 2024. See our QMI report for a description of the modelling methodology. This approach allows us to compare the deaths observed in the summer of 2024 with what might have been expected based on temperatures alone.

The modelled estimate for England for summer 2024 was 1,028 (95% CI: 866 to 1,155) heat-associated deaths (Figure 9). This is lower than the estimate derived using observed mortality (1,311 [95% CI: 929 to 1,692]). This indicates that overall, there were more heat-associated deaths observed in 2024 than would be expected based on summer mortality patterns in 2019 to 2023. However, the difference was not statistically significant, as shown by the overlapping 95% CIs.

When considering the best estimates for the individual heat episodes, there is some misalignment. For example, higher observed mortality than modelled was seen in E1 (by 188 deaths) and E2 (by 204 deaths), indicating a bigger impact than would have been predicted by the model at the observed temperatures. Conversely, E3 saw 69 fewer deaths observed, and E4 saw 73 fewer deaths observed, than predicted by the model. None of these differences are statistically significant, as shown by the overlapping 95% CIs in Figure 9.

Figure 9. Observed and modelled heat-associated deaths, England, summer 2024

Note: error bars represent 95% confidence intervals.

Table 9 in the accompanying spreadsheet shows modelled estimates for heat-associated mortality by heat episode. Observed estimates for heat-associated mortality can be found in Table 1 in the accompanying spreadsheet.

Further insights and contextual information

Summary of main messages

The summer of 2024 was the coolest summer for the UK since 2015. Only 4 heat episodes occurred, and no amber or red Heat Health Alerts (HHAs) were issued in any region of England. A full seasonal summary of the weather conditions for summer 2024 is available from the Met Office.

An estimated 1,311 (95% CI: 929 to 1,692) heat-associated deaths were observed. There were 282 more deaths than predicted, based on the observed temperatures in summer 2024 and the historic temperature-mortality relationship in England, though this difference was not statistically significant.

Despite the relatively cooler weather in 2024 than in recent summers with only yellow HHAs issued, significant heat-associated mortality was still observed in 3 of the 4 heat episodes that occurred. This included during short spells of heat lasting only 3 days. UKHSA has published guidance for the public and professionals on actions to protect health during hot weather. This includes action cards with recommended actions during yellow, amber and red HHAs to protect those most vulnerable and at greatest risk to the impacts of heat.

Considering the 4 individual heat episodes, the first 2 episodes E1 and E2 saw higher observed deaths than expected, whereas E3 and E4 saw lower deaths than expected. This is in agreement with academic research showing higher mortality risk in early-season heatwaves than later in the season. A possible reason for this is greater preparedness and acclimatisation to heat later in the summer. The later episodes E3 and E4 occurred during a period of prolonged warmer weather in late July and August. This could have contributed to behaviour changes meaning that the public and organisations were more prepared for the extreme temperatures in E3 and E4.

More work is required to assess the contribution of different factors beyond temperature to heat-associated mortality. Ongoing evaluation of the impact-based HHA system introduced in summer 2023 will support a better understanding of how alerts may have affected behaviour and response. In addition, UKHSA is planning epidemiological analysis using multiple years of data on heat-associated mortality. This will allow us to better understand the social, environmental and weather-related risk factors that drive mortality during heat episodes.

Heat episodes in England are predicted to become more intense, longer and more frequent due to climate change (Health Effects of Climate Change in the UK report, 2023). UKHSA has published the Adverse Weather and Health Plan for England, recently updated for 2025 to 2026. The plan aims to support local and national organisations to prepare for and respond to adverse weather events such as heatwaves, including emergency response and longer-term adaptation. These statistics form part of monitoring progress towards the plan’s goals to prevent mortality and years of life lost due to adverse weather and inform and improve future responses to heat.

Heat-associated deaths by geographical area

As in 2022 and 2023, the South East had the highest number of heat-associated deaths in 2024. However, when adjusting for population size, the West Midlands had the highest rate of heat-associated deaths per million population in 2024.

The highest rate per million population by LRF area was seen in Cleveland in the North East. This is an interesting result, especially since the North East region saw generally cooler temperatures in summer 2024 compared to other regions. The area covered by Cleveland LRF (the local authorities of Hartlepool, Middlesbrough, Redcar and Cleveland, and Stockton-on-Tees) includes areas with high deprivation and high prevalence of chronic diseases. This points towards the role of population risk factors as well as temperatures in determining the heat-associated mortality observed. However, the result for Cleveland LRF should be interpreted with caution considering the lack of statistical significance.

Overall, the breakdowns by region and LRF do not show any clear geographical pattern in heat-associated mortality in England in 2024. Population factors as well as temperatures are likely to play an important role in the number of deaths observed.

Heat-associated deaths by age group

As seen in previous years, the highest mortality was observed in older age groups, with significant heat-associated deaths in those aged 75 to 84 years and those aged 85 years and over. Though the observed number of deaths was higher in those aged 85 and over, the highest years of life lost were seen in those aged 75 to 84 years since they had a greater remaining life expectancy. 

In other recent years, heat-associated mortality has also been observed in younger age groups, such as those aged 65 to 74 years (in 2020, 2022 and 2023) and in those aged 45 to 64 years (in 2020), though this was not observed in 2024.

Heat-associated deaths by sex

There was no significant difference in heat-associated mortality between females and males in 2024, although the estimate was slightly higher for females than males. Some epidemiological research has reported a higher heat-associated mortality risk for women from high-income countries. Further research may help to understand potential differences in heat-associated mortality risk based on sex in England.

Heat-associated deaths by place of death

New analysis for 2024 found that the place of heat-associated deaths differed between heat episodes. Hospitals saw higher heat-associated deaths in E1 and E3, while deaths in people’s own residence were the leading place of death in E2. Care homes saw heat-associated deaths more consistently across all 4 episodes. This is an area that may benefit from further research to understand the factors involved in heat-associated deaths in these different settings.

Heat-associated deaths by cause of death

New analysis for 2024 by cause of death shows significant heat-associated deaths for ‘All circulatory diseases’, ‘Dementia and Alzheimer’s’ and ‘Influenza and pneumonia’ as underlying causes. Heat-associated deaths were not statistically significant for the causes ‘Cancer’, ‘Chronic lower respiratory diseases’ or ‘External causes’, although these causes have been linked with heat-associated mortality in some epidemiological research. Further research in this area may help to understand how chronic diseases contribute to risk of mortality during heat episodes.

Glossary

Central England Temperature (CET)

A temperature data set produced by the Met Office Hadley Centre, which is representative of the temperature in a roughly triangular area of the United Kingdom enclosed by Lancashire, London and Bristol.

Confidence interval (CI)

A confidence interval is a measure of the degree of uncertainty in an estimate. 95% confidence intervals indicate that we are 95% confident that the range includes the true value of the estimate. A wider range indicates more uncertainty in the estimate. Overlapping confidence intervals indicate that there may not be a true difference between estimates.

Heat episode

A period of heat, defined for this analysis based on an amber Heat Health Alert (HHA) in at least one region or when the mean Central England Temperature (CET) is at least 20°C.

Heat Health Alert (HHA)

An alert issued by England’s Weather Health Alerting system, warning that hot weather is forecast that could lead to impacts on health for the population of England. Alerts can be issued at yellow (response), amber (enhanced response) or red (emergency response) levels.

Local resilience forum (LRF)

A multi-agency partnership made up of representatives from local public services with responsibilities for emergency preparedness, resilience and response. The geographical areas they cover are based on police areas.

Data sources and methodology

Our QMI report explains our calculations in further detail.

Heat episodes are identified whenever there is an amber HHA in at least one region of England, or the mean CET reaches at least 20°C. One day either side is also included. For the first heat episode in 2024, E1, mean CET reached 20°C on 26 June 2024. Both of the previous two days (24 June and 25 June) have been included in E1, because there was a sharp increase in temperature starting from 24 June 2024, which was the hottest day of the year so far.

The number of observed heat-associated deaths is calculated by comparing daily deaths during a heat episode with daily deaths in 14-day baseline periods, before and after the heat episode. Because of random variation in daily deaths not related to heat, there is uncertainty in whether all excess deaths during a heat episode can be attributed to heat. The uncertainty is represented by the 95% confidence intervals shown in brackets after each estimate. Reported numbers are considered to be significant if the 95% confidence intervals (shown in brackets after each estimate) do not overlap with zero.

The modelled estimate for heat-associated deaths is calculated using a statistical model of the temperature-mortality relationship in England over the previous 5 years. The model estimates the relative risk of mortality for any given temperature above the median summer temperature. This risk is applied to the actual temperatures observed in the summer of 2024, to generate a prediction of the expected number of deaths for the temperature and time of year on each heat episode day.

Background information

Related statistics

• Previous UKHSA annual heat mortality monitoring reports
• UKHSA weekly all-cause mortality surveillance
• UKHSA annual surveillance of influenza and other seasonal respiratory viruses in the UK

Other assessments of mortality include the number of weekly deaths registered in England and Wales, which is published weekly by the Office for National Statistics (ONS).

The Office for Health Improvement and Disparities also produces the Excess mortality within England report, which provides estimates of expected deaths by month of registration for population subgroups and by cause of death.

The different methods used in the UK for mortality assessment, and their varied purposes, are discussed in more detail in Measuring excess mortality: a guide to the main reports.

In 2023 the ONS also published experimental statistics on climate-related mortality in England and Wales, 1988 to 2022.

Further information and contact details

Feedback and contact information

For any feedback or enquiries, please contact: extremeevents@ukhsa.gov.uk

We are carrying out a user survey to gather your views and shape the future of our publication.

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