The U.K. on Friday issued a “Red Extreme” heat warning, with authorities saying temperatures could potentially hit 40 degrees Celsius (104 Fahrenheit) next week.

In a statement, the Met Office said the warning would cover parts of eastern, southeastern, central and northern England on July 18 and 19.

“Exceptional, perhaps record-breaking temperatures are likely early next week, quite widely across the red warning area on Monday, and focused a little more east and north on Tuesday,” Paul Gundersen, chief meteorologist at the Met Office, said.

“Currently there is a 50% chance we could see temperatures top 40°C and 80% we will see a new maximum temperature reached,” Gundersen said.

Friday’s new heat warning came on the same day the U.K. Health Security Agency issued a Level 4 Heat-Health Warning for England. The warning runs between midnight on Monday and midnight on Wednesday next week.

According to the Met Office, Level 4 denotes a national emergency and takes place “when a heatwave is so severe and/or prolonged that its effects extend outside the health and social care system.”

“At this level, illness and death may occur among the fit and healthy, and not just in high-risk groups,” it adds.

People are being advised to take a number of actions to cope with the heat. These include:

• Looking out for young children and babies, older people, and people with underlying health conditions.
• Closing curtains in rooms facing the sun.
• Dressing appropriately in relation to the weather.
• Avoiding excess alcohol.
• And drinking “plenty of fluids.”

The U.K.’s record high temperature stands at 38.7 degrees Celsius. That was reached on July 25, 2019, in Cambridge.

Parts of the U.K. have experienced uncomfortably hot weather in recent days, with an Amber Extreme heat warning already issued between July 17 and 19 for a significant chunk of England and Wales.

“Temperatures are expected to start to return closer to normal for the time of year from the middle of next week onwards as cooler air pushes across the country from the west,” the Met Office said.

In January 2022, the World Meteorological Organization said 2021 had been “one of the seven warmest years on record.” The WMO based its finding on the consolidation of six international datasets.

In a statement at the time, the WMO said global warming and what it called “other long-term climate change trends” were “expected to continue as a result of record levels of heat-trapping greenhouse gases in the atmosphere.”

Back in the U.K., Nikos Christidis, climate attribution scientist at the Met Office, said climate change had “already influenced the likelihood of temperature extremes in the UK.”

“The chances of seeing 40°C days in the UK could be as much as 10 times more likely in the current climate than under a natural climate unaffected by human influence,” Christidis added.