Heatwaves in the UK pose a threat of wildfires, disruption to transport and power systems, and even a risk to life.
The Met Office has forecasted that the UK is set to experience highs of 34C this weekend, with large swathes of the country enjoying temperatures around 30C.
In anticipation of what is likely to be an official heatwave, amber heat-health alerts have been issued by the UK Health Security Agency (UKHSA).
These warnings suggest that the entire health service is “likely” to be affected by high temperatures, with a “rise in deaths” expected.
While 30C may cause widespread disruption in the UK, for many European holiday destinations, this temperature can feel quite pleasant.
If you’ve ever felt that hot weather in the UK feels more intense than when you’re on holiday abroad, you’re not alone, reports the Manchester Evening News.
While temperatures above 30C might feel comfortable in Spain, Portugal or Italy, the same temperature can feel unbearable at home.
British heat does indeed feel different – and there’s a reason why it feels hotter.
Annie Shuttleworth, a meteorologist from the Met Office, told Stylist : “It is perhaps how heatwaves in the UK are perceived that makes them less manageable. When we experience heat abroad, we’re usually on holiday, and may be close to a pool or the beach. In general, buildings and infrastructure are also more set up for heat abroad – for example, there is more air conditioning.”
And it’s not just a figment of your imagination; humidity also plays a part in why 30C feels hotter in the UK than abroad.
A Met Office spokesperson explained to MyLondon in 2021 why the UK’s humidity can make heatwaves particularly challenging. “The level of humidity can be higher in the UK than in continental Europe. If humidity is high, it is harder for the human body to keep cool as your sweat doesn’t evaporate as quickly.”
They also highlighted the increasing occurrence of ‘tropical nights’ – a phenomenon where temperatures stay above 20C throughout the night, offering no relief from the heat and preventing our bodies from recovering.
Our body’s ability to lose heat depends on the temperature difference between our skin and the surrounding air, but this process is less efficient when external temperatures rise.
Sweat plays a crucial role in cooling us down through evaporation, yet high humidity levels can hinder this natural cooling mechanism.
“Sweating cools you down because when the water evaporates it transfers energy away from your body. However, sweating is less effective if there is already a lot of moisture in the air,” said Dr Matthew Patterson, a meteorologist, while speaking with BBC Science Focus.
This explains why the humid heat in the UK can feel more oppressive than the heat experienced in many other European countries and why health and weather warnings may be issued in the UK for temperatures in the low 30s, which might not be considered extreme elsewhere.
Climate expert Prof Hannah Cloke explained to BBC Science Focus how meteorologists and health organisations use various indicators to assess the impact that temperature, humidity, and wind speed have on our bodies.
“Forecasters and health agencies measure and forecast the effects of temperature, humidity and windspeed on the human body in terms of a ‘feels like’ temperature, or with indicators such as the Universal Thermal Climate Index (UTCI),” she said.
Prof Cloke highlighted why these measures are crucial for more than just statistical data: “Two regions might have identical temperatures, but one might feel OK, while the other leaves people dangerously overheated. Measures like the UTCI can provide planners with a much better understanding of where and when the impacts of a heatwave will be felt.”
Looking for more from MyLondon? Subscribe to our daily newsletters here for the latest and greatest updates from across London.
