Heatwave in England to bring temperatures above 32°C (89.6°F) – study finds climate change made this 100 times more likely

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Heatwaves – one of the most dangerous weather hazards – have already increased in severity and frequency at a global scale since the 1950s, mainly driven by climate change^[1].

Despite the evidence, some still downplay these hazards, often by spreading misinformation that climate change isn’t linked in any way. Some even criticize map colors to make their point instead of focusing on the actual numbers: so let’s take a look at what the data shows.

A 2021 study found that from 2000 to 2019, roughly 489,000 heat-related deaths occurred each year^[2] – more than 70,000 of those occurred during the 2003 heatwave in Europe. And the Intergovernmental Panel on Climate Change (IPCC) explains – with virtual certainty – that human-caused climate change is driving the rise in heatwaves^[1].

This week many are facing harsh conditions as the first heatwave of 2025 just hit the UK. The heatwave in the UK triggered the UK Health Security Agency (UKHSA) to issue an alert for all of England, warning of significant heat-related health risks from Thursday 19 June 2025 to Monday 23 June. Over this period, widespread temperatures of 32°C (89.6°F) are expected, with some areas potentially hitting 34°C (93.2°F).

After becoming aware of this, scientists rapidly studied how climate change may have influenced this event. The results of this study were published on 20 June 2025 by World Weather Attribution (WWA) – a group of scientists who rapidly study how climate change has influenced the intensity and likelihood of extreme weather events when they occur.

Below, we will summarize these freshly released findings.

Main Takeaways:

The first heatwave of 2025 hit England in June, quickly shifting conditions from comfortable sunny days to a dangerous heatwave, triggering country-wide amber heat health alerts.
Scientists from World Weather Attribution (WWA) conducted a rapid analysis of the June 2025 England heatwave, revealing that climate change increased both the likelihood of the heatwave itself and of the single-day high temperatures.
WWA study finds human-driven climate change made it 100 times more likely that temperature would climb above 32°C (89.6°F) on June day in southeast England.
WWA study finds human-driven climate change made it 10 times more likely that a heatwave with three consecutive days above 28°C (82.4°F) would occur in June in southeast England.
Although this study was conducted quickly, the findings agree with a more robust 2022 study from WWA of a similar region in the UK, giving scientists high confidence in the results

Temperatures above 32°C (89.6°F) in southeast England 100x more likely due to human-driven climate change, according to WWA study

This event unfolded rather quickly. At first, a high-pressure system – which gives clear skies and gentle wind – brought sunny, mild conditions in the week of 16 June, but temperatures quickly rose as southerly winds drew warm air into the South of England.

Now, forecasts predict that on Saturday 21 June 2025, temperatures above 32°C (89.6°F) will be widespread in England over several days, meeting the UK definition* of a heatwave (Figure 1).

*Note: the definition of a heatwave can vary according to region based on the normal temperatures experienced there.

WWA’s early analysis of this event – which is ongoing as we write this – found that human-driven climate change makes these high temperatures in June roughly 100 times more likely.

In the report, Dr. Ben Clarke, Researcher at the Centre for Environmental Policy Imperial College London, explains:

“This heatwave is another reminder that our planet has already heated to a dangerous level. We’re at 1.3°C today, but heading for around 3°C this century. With every fraction of a degree of warming, the UK will experience hotter, more dangerous heatwaves. That means more heat deaths, more pressure on the NHS, more transport disruptions, tougher work conditions and poorer air quality.”

WWA studied the unusually high June temperatures that are underway by analyzing extreme high temperatures occurring in June from past years. WWA pointed out that this was considered a ‘super rapid analysis’, rather than a full attribution study. A full study would require the event to finish so they could analyze what was observed.

However, WWA has high confidence in the findings given that they align with the results of a full attribution study they did for a similar region in the UK after an extreme heatwave in 2022. That study showed that climate change made the 2022 UK heatwave – which brought temperatures as high as 40.3°C (104.5°F) – 10 times more likely to occur.

Although expected temperatures are lower for the current event, WWA’s rapid analysis shows a similar influence from climate change. Today’s global temperatures are 1.3°C warmer than pre-industrial temperatures – the June 2025 WWA analysis found that this warming has made it 100 times more likely for a single June day in southeast England to climb above 32°C (89.6°F).

WWA created a graphic to visualize this (Figure 2), showing that such an occurrence rose from being a 1 in 2,500-year event to a 1 in 25-year event – a 100x increase in likelihood. WWA explains that this finding shows that the chance of experiencing the most intense heatwaves is rapidly growing.

In addition to single-day high temperatures, WWA also analyzed the heatwave itself – that is, as a collection of days with extreme heat. The WWA visual below (Figure 3) shows how often we should expect southeast England to meet the heatwave threshold which, in this study region of the UK, is defined as having three days above 28°C (82.4°F).

As shown below, WWA found that global warming has led to a 10x increase in likelihood that southeast England will meet the heatwave threshold in June – going from a 1 in 50-year event to a 1 in 5-year event. In other words, southeast England has a 20% chance of crossing that heatwave threshold in a given year, compared to only a 2% chance prior to human-driven climate change.

As noted earlier, these results agree with a more robust study conducted by WWA on a similar region of the UK. That 2022 study found that the most extreme heat-waves have become 2°C hotter due to human-driven climate change.

While the WWA rapid analysis results for the ongoing event have been published, scientists will likely offer deeper insights as the event plays out. Keep an eye out for updates from World Weather Attribution on their heat wave analyses page.

Humans can help mitigate the severity and frequency of future heatwaves by lowering emissions, lessening human-health impacts

Regions all around the world experience rising temperatures in summer, but it would be foolish to shrug off heatwaves as just being ‘hot weather’. Heatwaves can be dangerous to our health and disrupt society in numerous ways.

As explained by the World Health Organization (WHO), “Heatwaves are among the most dangerous of natural hazards, but rarely receive adequate attention because their death tolls and destruction are not always immediately obvious.” WHO also explains that heatwaves pose challenges for emergency response services, and can put a strain on resources like water, transportation, and energy.

So, what can we expect in the future? This largely depends on how much we increase global temperatures. Without cutting emissions, the world will continue warming and heatwaves will worsen^[3]. As the IPCC explains:

“Relative to present-day conditions, changes in the intensity of extremes would be at least double at 2°C, and quadruple at 3°C of global warming, compared to changes at 1.5°C of global warming.”^[1]

In addition to limiting warming through cutting emissions, there are also adaptation and preparation measures. As WHO explains:

“The magnitude of human costs from heatwaves can be reduced if adequate emergency prevention, preparedness, response and recovery measures are implemented in a sustainable and timely manner.”

The balance between these is to be struck by policy makers and informed decisions from society. But as temperatures climb this summer, let it be a reminder: our actions today have future consequences – and not for us alone, but the world at large.