Not all heatwaves across the UK feel equal — here’s why
While the south boils in 33C weather, the north and Scotland enjoy cloudy, pleasant temperatures of 25C. Have you been wondering why the heatwave feels so different depending on where in the UK you are? The answer lies with the UK’s varied climate zones, the way the Met Office defines a heatwave, and how geography affects heat intensity and overnight temperatures.
How does the Met Office define a heatwave?
The Met Office defines a heatwave as three consecutive days where daily maximum temperatures meet or exceed a certain threshold, which varies by county.
For example, Greater London’s threshold is 28°C, in Surrey, Kent, and Essex, it’s 27°C, in northern England and Scotland, it’s just 25°C.
These thresholds reflect the 90th percentile of July temperatures in each area between 1991 and 2020 — so the bar is lower in cooler parts of the UK, but the heat still hits just as hard locally.
Why the same temperature feels different
Humidity differs in every UK city – this means that even if the thermometer reads the same in Manchester and Milton Keynes, the experience can vary.
Urban areas with less trees and greenery, like London and Birmingham, will retain more heat overnight.
Western and northern areas get better air circulation, and also benefit from wind direction. This is why these areas seem cooler compared to their southern counterparts.
Topography matters as well. As you move up north to areas like Cornwall, Cumbria, or the Highlands, elevated lands and proximity to the coast keeps them cooler. As the south is flatter and drier, the land tends to trap heat inward.
Is it still a heatwave if it’s cooler up north?
Yes – if the temperature in your region meets or exceeds your local threshold, it’s officially a heatwave. Even 25°C in Edinburgh can be enough to prompt health alerts because it’s significantly above average for that region.
While temperatures vary from 35C to 25C in different parts of the UK, the effects of the heatwave are felt everywhere. But as climate change propels more frequent and intense hot spells, understanding how your local area responds to heat will matter more than ever — not just what's happening in London.