Heatwaves: The UK’s Overlooked Climate Threat

The UK has experienced four heatwaves in 2025, reflecting the increasing frequency of extreme hot weather generally. Research from the Royal Meteorological Society shows that, when comparing the 2014-2023 period and the 1961-1990 period, the annual number of ‘hot’ days (28°C) more than doubled, and the number of ‘very hot’ days (30°C) and ‘extremely hot’ (32°C) days more than tripled. Despite this, extreme heat is often seen as a secondary concern to flooding and storms when people consider climate change, when it should be front and centre alongside these issues. 

Over the last year, Public First has conducted various research projects exploring how exposed local areas are to ongoing hotter temperatures, and public attitudes towards heatwaves. This blog draws on numerous research methods including polling, expert stakeholder interviews and data mapping, as well as analysing external data to demonstrate the impacts of heatwaves in the UK and assess public sentiment. 

Source: Public First Analysis of Royal Meteorological Society data (2025)

The Invisible Danger of Heatwaves

While Britain is preoccupied with wet weather, a culturally underappreciated climate challenge lies in rising temperatures. Prolonged heatwaves are a growing risk to both the financial and physical health of the nation.

People are more concerned about flooding and flooding-related issues than heat-related issues. Public First Polling conducted in September 2024 showed that 55% of people thought Flooding would be one of the effects of climate change that would have the greatest impact on the UK in the next 10 years. By comparison, only 42% of people thought Extreme Heat would be. Extreme Heat was also beaten by Severe Storms (48%), Sea level rise and Coastal Erosion (47%) and Energy Supply Issues (44%).

Heatwaves have measurable impacts on the UK economy. Increased temperatures impact worker productivity, especially in industries where adaptation and mitigation measures are harder to implement, such as in construction and agriculture. In our report From Risk to Resilience, we estimated that flooding costs the UK economy £6.1bn per year in lost GVA due to flooding events that have happened in the previous 5-10 years. Analysis by the Office for National Statistics shows that GVA losses due to hot days averaged £3bn per year in the 5 year period from 2016 to 2020 - nearly 50% of the flooding figure. 

While flooding may pose a greater threat to the economy than heatwaves, the impact of increased heat on productivity is significant and represents huge losses.

Heatwaves also have an acute impact on health, especially when compared to flooding. While flooding causes more damage to property and a greater loss in productivity, deaths directly caused by flooding events tend to be minimal. For example, the major floods of 2019/2020 resulted in 11 excess deaths, whereas annual excess heat-related deaths in 2020 alone were estimated to be 2,556.

Source: PF Analysis of ONS data

In recent polling from June 2025, 57% of people said the hot weather had made it uncomfortable to be indoors, and 66% said that the hot weather had made it difficult to sleep. People also experienced other issues related to the heat, such as being irritable (42%), having difficulty focussing (41%) and minor health issues such as headaches (35%).

In the same polling, we found that 74% of people thought the UK was not well prepared for very hot summers, and 69% of people thought that the UK struggles to function in very high temperatures. Furthermore, 56% of people agreed that hot weather causes too much disruption in the UK, and 50% agreed that heat related health issues are not taken seriously enough.

Interviews with expert stakeholders suggest that one of the largest issues with addressing extreme heat in the UK is simply that the weather is perceived as being perennially cold and wet. As a result, the issue of heat is not yet seen to be bad enough to warrant action.

While our polling and opinion research looks at attitudes among the general public, our research for AXA UK highlights how not all communities experience extreme heat in the same way. We mapped the constituencies most at risk of extreme heat events due to climate change by constructing an index from a combination of geographical and socioeconomic factors.

We found that all 10 constituencies most at risk of extreme heat were currently in London.

The fact that London dominates the most vulnerable constituencies is symptomatic of an anthropogenic heating phenomenon. Our map shows a trend of more inland areas, specifically urban areas, being more vulnerable to heat risks. The phenomenon of Urban Heat Islands (UHIs) is defined by the fact that built-up areas experience significantly higher temperatures than surrounding rural areas. This is due to the concentration of surfaces with high heat absorbance such as concrete and tarmac, as well as reduced vegetation. Research has shown that urban heat islands can exacerbate heatwave impacts, particularly in inland urban areas where there is a lack of cooling sea breezes, leading to sustained high temperatures at night. London consistently exhibits strong UHI effects, with a study by the Greater London Authority identifying temperature differentials of up to 10°C between the city centre and surrounding rural areas during summer heatwaves. These intensification effects are especially pronounced in densely built inland districts, where older housing stock, limited green space, and high population density contribute to heat vulnerability. This is supported by our Socio-Economic Index ranks, shown in Table 1. All of the top 10 constituencies rank in the top 15 when ranked on their socio-economic standing (higher rank equals more socio-economically vulnerable).  

The Politics of Heatwaves

All of the top 10 most vulnerable constituencies were won by Labour in the 2024 general election. The relationship between politics and climate issues is an important one - exposure to climate risks shapes local issues and constituency priorities, putting pressure on MPs to deliver adaptation and resilience measures. A poll we conducted in February 2025 found that out of all the political parties in the UK, Labour is the one most trusted to deal with extreme weather events both now (19%) and moving forward (19%), followed by the Green Party (16% and 17% respectively), then the Conservatives (14% and 12% respectively). The Lib Dems were the least trusted (7% and 6% respectively).

While Labour is seen to be the most prepared out of the available options, the public still view the party as unprepared generally. In the same poll, 65% of people said that the current Labour government was not prepared to deal with extreme weather events - this includes 47% of Labour voters. Reform voters exhibited particularly low confidence - only 15% of them thought the current Government was at all prepared.

The issue of extreme heat in the UK is not partisan. All voters, including right-leaning voters, acknowledge that it is becoming more common in the UK. Green Party voters and Lib Dem voters have the highest rate of acknowledgement of very hot weather becoming more common (83%) and Reform the lowest, with a still significant 63%. Voters for all parties are similarly likely to agree that the country struggles to function in very high temperatures, with Green Party voters agreeing the most often (74%) and Conservative voters the least (69%).

As heatwaves intensify and disrupt daily life in the UK, the politics of heat will likely shift, forcing policy to catch up.