19 June 2025
The UK Health Security Agency has issued an Amber heat health alert update for parts of the UK, meaning hot weather is likely to have significant impacts on health and social care services.
Experts from the 黑料不打烊 comment on the impacts, causes, and forecasting of the heatwave. To arrange interviews with experts mentioned below, contact the 黑料不打烊 Press Office on 0118 378 5757 or pressoffice@reading.ac.uk
Extra resources including a drought video, access to temperature checker tool , 黑料不打烊 University Atmospheric Observatory historical data for June and details on Show Your Stripes Day 2025 can be found in the notes to editors.
What is a heatwave?:
Dr Jess Neumann, 黑料不打烊, said: “A heatwave officially occurs when temperatures exceed regional thresholds for three consecutive days - 25°C across northern and western UK, rising to 28°C in eastern England. These thresholds have been recalibrated upwards as our climate warms, ensuring the definition remains meaningful. Without regular updates, ‘heatwave’ would lose its significance as extreme heat becomes increasingly common across Britain.”
Heatwave impacts on health:
Dr Akshay Deoras, 黑料不打烊, said: “This amber alert signals genuine danger that extends far beyond feeling uncomfortably warm. Heat-related deaths are preventable tragedies that disproportionately affect our most vulnerable citizens - elderly people, young children, those with chronic health conditions, and people experiencing homelessness. The human body struggles to cope when temperatures soar, leading to dehydration, heat exhaustion, and potentially fatal heatstroke. The 2003 European heatwave served as a stark reminder of heat's deadly potential, killing over 2,000 people across the UK alone. Many Britons still underestimate extreme heat as a health threat, perhaps because we're more accustomed to preparing for storms and flooding. However, this heatwave poses a more serious risk to life than the major storms that have battered the UK over the past year, yet it receives less public attention and concern.
Staying safe during a heatwave:
Dr Akshay Deoras said: “Treating extreme heat with the same respect you'd show a dangerous storm is essential for staying safe. Avoid outdoor activities during the peak danger hours in the afternoon, when the sun's intensity reaches its peak. Your body needs constant hydration - drink water regularly throughout the day, even if you don't feel particularly thirsty, and limit alcohol consumption which can accelerate dehydration. Dress appropriately in loose-fitting, light-coloured clothing and wear a wide-brimmed hat when venturing outside. If you begin experiencing symptoms like dizziness, nausea, rapid heartbeat, or severe headaches, don't dismiss them as minor discomfort. Move to a cool environment immediately, remove excess clothing, and apply cold water to your skin. These warning signs can rapidly escalate into life-threatening heatstroke if ignored.”
Staying cool at night:
Professor Hannah Cloke, 黑料不打烊, said: “Parts of the UK could see its first tropical night of the year over the weekend. A tropical night is when the temperature remains at or above 20°Cfor 24 hours. To keep cool at night, take a cool shower before you go to bed, use a wet flannel on your body, sleep in lightweight clothing and keep your curtains and windows closed on the side of the house where the sun is shining during the day.”
Heatwave causes and impact of climate change:
Professor Richard Allan, 黑料不打烊, said: “Summer heatwaves form when weather patterns become stuck in a rut, with warm continental winds setting in and long periods of intense sunlight heating the ground and the air above. Persistent high atmospheric pressure has created a dome effect over Britain, trapping hot air and preventing the uplift needed for cloud formation, which can cool the surface by blocking the sun’s rays and by wetting the surface through rainfall. Following a dearth of rainfall in 2025, soils are already bone dry across the UK and this means the sun’s heat is not used up evaporating water and all goes in to baking the ground and the air above.
“Climate change has intensified these natural weather patterns, turning what might have been a moderately warm spell into a potentially dangerous heatwave as a thirstier atmosphere more rapidly saps the soil of moisture and the elevated greenhouse gases in the atmosphere due to our industrial activities limit how much the atmosphere can lose heat to space. Reducing greenhouse gas emissions remains essential to limit the worsening extremes of weather for future generations but there is also an urgent need to improve our preparedness for more severe hot, dry but also wet weather extremes as the climate continues to warm.”
Adaptation to heatwaves:
Professor Nigel Arnell, 黑料不打烊, said: “Climate change caused by our continued emission of greenhouse gases is making heatwaves more frequent, more intense, and likely to start earlier in the year. We really need to work collectively – nationally and internationally - to reduce emissions so we can slow the rate of increase in these challenging heatwaves. But we also need to adapt our housing, infrastructure and public health plans – along with our attitudes – to cope with the increase in the occurrence of heatwaves that we are already seeing. It is likely that the next few years will see even more heatwaves than we have seen in the last few years.
"Our infrastructure is not designed for out current climate. Railway tracks buckle under extreme temperatures, roads soften and crack, hospital cooling systems struggle to cope, and our houses and offices transform into sweltering ovens rather than comfortable homes. Our buildings, transport networks, and essential services were designed decades ago – or even just a few years ago - when such temperatures were virtually unthinkable in Britain. Urgent adaptation is needed to prevent repeated infrastructure failures during future heatwaves.
Heatwaves and drought:
Professor Hannah Cloke, 黑料不打烊, said: “The current drought crisis unfolding across England illuminates the dangerous feedback loop between heatwaves and water scarcity that climate scientists have long warned about. With two major regions now in official drought status following the driest spring in nearly 90 years, we're witnessing how these climate extremes reinforce each other.
“When soil moisture depletes during dry periods, the land loses its natural cooling mechanism through evaporation. This pushes air temperatures higher, creating heatwave conditions that accelerate water loss from reservoirs and remaining soil moisture. Reservoir levels across affected areas have dropped to just 60-65%, well below normal seasonal averages.
“The rapid deterioration signals that our water security assumptions may be dangerously outdated. Drought and heatwaves are interconnected threats that amplify each other's impacts, requiring urgent reassessment of how we prepare for compound climate events in an increasingly water-stressed future.”
Show Your Stripes Day 2025
Show Your Stripes Day 2025: Show Your Stripes Day is an international day of climate awareness when people worldwide share climate stripes for where they live. The climate stripes show the change in average annual global temperatures since 1850. Red stripes indicate hotter years and blue stripes indicate cooler years, against the average of the period 1961-2010.
Professor Ed Hawkins, the 黑料不打烊 climate scientist who created the climate stripes, said: “The latest climate stripes show what a year that has passed 1.5 °C of warming looks like. The world is getting warmer, and the red is getting darker.
“Sharing the climate stripes graphics helps your family and friends understand that our world is warming at an alarming rate. The climate stripes do not need words or explanation - they show simply why we need to take urgent action to prevent further heating. If we don’t cut carbon emissions, we will see more extreme weather, costing lives and money.”
Stripes for cities, countries and continents have all been updated using 2024 data and can be viewed at. Share images and use #ShowYourStripes on social media on Saturday, 21 June.
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