The third heatwave of the year has started across parts of the United Kingdom, with temperatures expected to rise up to 34C in London and south-east England by Wednesday and Thursday. Unlike the record-breaking June heatwave, which peaked at 37.7C, this one is not likely to be as extreme – but it is forecast to last longer.
Simon King, the BBC's lead weather presenter, said the current forecasts suggest a temperature exceeding 30C somewhere in the UK is likely for up to 10 consecutive days. That would exceed the seven consecutive days of 30C-plus seen in June, and the six days in May.
“UK's third heatwave starts, less extreme than June's 37.7C but likely to last up to 10 days above 30C.”
The first two heatwaves of the year were record-breaking. New monthly temperature records were set by a significant margin in May (35.1C) and June (37.7C). June's heatwave also brought extremely high humidity, making it feel as if temperatures were above 40C in some locations, along with several "tropical nights" where the temperature did not fall below 20C. Amber and red heat-health alerts were issued, and the Met Office issued a rare red warning for extreme heat at the end of June.
This week's heatwave is not expected to bring the same extreme temperatures or high humidity. Instead, yellow heat-health alerts from the UK Health Security Agency have been issued across the Midlands and southern England until 20:00 GMT on 11 July. The UKHSA suggests minor impacts are expected across health and social care services, with a greater risk to life for vulnerable people.
On Monday afternoon, temperatures across the Midlands, East Anglia and south-east England could rise to 31C. With temperatures above 28C expected, the official heatwave criteria will be met widely in these locations over the next few days. The heatwave will then intensify from mid-week, with temperatures across England and east Wales getting into the high-20s and low-30s. The peak is expected in London and south-east England, where the mercury may reach around 34C on Wednesday and Thursday.
Although it is unlikely to reach the 37.7C recorded at the end of June, some weather forecasting models suggest there is a chance of mid to high-30s later in the week. The UK all-time temperature record of 40.3C was set in July 2022 at Coningsby, Lincolnshire.
Northern areas of the UK will turn warmer but cloud and rain is likely to continue, particularly in western Scotland. Significant heat has been building in Portugal and across Europe, which is contributing to the prolonged warm spell affecting the UK.
The longer-lasting nature of this heatwave – potentially 10 consecutive days above 30C – could test infrastructure and public health systems, particularly for the elderly and those with underlying conditions, even without the extreme peaks seen in June.