Why British Heatwaves Feel Hotter Than They Are
- Connor Banks
- Jul 1
- 3 min read
Every summer, a familiar complaint echoes across Britain: Why does this heat feel so unbearable?
Even when temperatures stay lower than those in Spain or Italy, British heatwaves often feel surprisingly oppressive. The reasons are rooted in the unique blend of Britain’s climate, urban design, and human physiology, with a healthy dose of psychology thrown in.
Britain: Built for Cold, Not Heat
Britain’s housing stock was designed for a cool, damp climate. Historically, keeping warm was the priority, not staying cool.
Heat-Trapping Buildings: Many homes use materials like brick, stone, and concrete, which absorb heat during the day and release it slowly at night. In winter, that’s helpful. In summer, it turns houses into slow-cooking ovens.
Insulation and Small Windows: Homes are insulated to conserve heat, and older designs often feature small windows that limit ventilation.
Lack of Air Conditioning: Unlike hotter countries, air conditioning remains rare in British homes and many public buildings. During a heatwave, there’s often nowhere to cool off.
All these factors mean that once heat enters British buildings, it’s hard to get it out.
Urban Heat Islands: Cities That Can’t Cool Down
British cities suffer from what scientists call the Urban Heat Island effect.
Dark Surfaces: Materials like tarmac and concrete absorb more sunlight than natural landscapes and radiate heat back into the air.
Reduced Green Space: Trees and plants cool cities through shade and evaporation. Urban development often replaces these with hard surfaces, intensifying heat.
Heat from Human Activity: Cars, buses, and even electronics add extra heat to urban air.
During heatwaves, cities like London can be several degrees hotter than surrounding rural areas, especially at night, when trapped heat struggles to escape. This makes sleeping difficult, leaving people tired and less able to cope with heat stress the next day.
The Weather Whiplash Factor
One of the UK’s defining weather traits is how quickly it changes.
Britain sits at the crossroads of several major air masses:
Cool, moist Atlantic air from the west
Hot, dry air from continental Europe to the south and southeast
Polar maritime air from the north
The position of the jet stream — a fast-moving river of air high in the atmosphere — determines which air mass dominates. During a heatwave, a strong area of high pressure often parks over the UK, blocking cooler Atlantic systems. But the jet stream can shift suddenly, sweeping in cooler air and ending a heatwave almost overnight.
This means British people can go from 33°C one day to 19°C and drizzle the next. Such wild swings give no time for the body to gradually adjust.
Humidity Makes It Worse
A common misconception is that British heatwaves are always dry. In reality, some arrive with high humidity, depending on where the hot air comes from.
Atlantic Influence: Hot air drawn from the southwest often carries significant moisture from the ocean.
Sweat Struggles: Humidity slows down the evaporation of sweat, the body’s natural cooling system. Even temperatures around 28–30°C can feel stifling if the humidity is high.
This explains why moderate British heat can sometimes feel more exhausting than higher, dry heat in places like Spain.
We’re Just Not Used to It
Humans adapt surprisingly well to heat if given time. People in warmer countries:
Start sweating earlier during heat exposure
Produce more sweat
Have lower heart rates and less strain under heat stress
In Britain, heatwaves are still relatively rare. Most people simply aren’t physiologically or psychologically acclimatised to handle high temperatures.
There’s also a cultural dimension. In Mediterranean countries, summer heat is normal. Daily life adapts with siestas, shaded streets, and social expectations to slow down. In Britain, people try to carry on as usual — until trains slow down, roads melt, and newspapers scream about record-breaking temperatures.
Climate Change: Turning Up the Heat
Climate change is making British heatwaves longer, hotter, and more frequent. In July 2022, Britain surpassed 40°C for the first time in recorded history. Events once considered “freak weather” are becoming part of the new normal.
Yet infrastructure, housing, and social habits have barely caught up. Without adaptation, the effects of heatwaves on health, productivity, and quality of life will only worsen.
British Heatwaves: The Bottom Line
British heatwaves feel more severe than the thermometer suggests because the country’s buildings, cities, and people simply aren’t built for sustained heat. And with climate change raising the stakes, it’s a challenge the UK can no longer afford to ignore.
