What Europe’s 40°C ‘heat dome’ means for another UK heatwave

The second heatwave of 2026 is about to hit southern and eastern England over the next week, but the north and west of the UK are set for more typical temperatures for the time of year and even some rain.

The stark contrast in weather patterns for the country is all down to the “heat dome” currently squatting over Europe, sending temperatures soaring in France, Spain and Italy, and reaching 40°C in some places.

Britain is on the boundary between this high pressure system and a low pressure system to the north, meaning that people across the country are experiencing markedly different temperatures.

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Heat domes usually occur in summer , when an area of high pressure in the upper atmosphere stays over the same area, as is now happening in Europe.

Air near the ground warmed by the Sun should rise, but is trapped in place by the high pressure, which acts like a lid over the dome. “This allows temperatures to build, day on day, as the sunshine heats the surface,” said a Met Office spokesperson.

This is compounded by a second effect. Air trapped by the lid ends up sinking and compressing, which further raises its temperature.

“This plays a key role in elevating temperatures day on day,” said the spokesperson.

The southern and eastern parts of England are on the edge of the heat dome, and so could share Europe’s unseasonally hot weather over the next week or so.

Temperatures are expected to reach the low 30s in the south and east of the UK by this Friday, and there could be thunderstorms.

Tourists cool off at a fountain near the Pantheon during a heatwave in Rome (Photo: Vincenzo Livieri/Reuters)

A heatwave is defined as three consecutive days of high temperatures.

In the west and north of Britain, though, low pressure will continue to feed in areas of cloud, rain and fresher air.

A “baroclinic zone” – a boundary between warm and cool air masses – will be situated squarely across the UK.

In northern and western areas, “this will result in a ‘waving’ front, where bands of rain ebb and flow over several days”, the Met Office said in a blog post . “This creates a pronounced north–west to south–east temperature gradient across the UK.”

But those who are unsatisfied with their weather forecast should spare a thought for Europeans, some of whom may experience temperatures 10°C above normal.