Market News

The sunny spring is set to give way to a warm summer in the coming months, but that brings increased risk of heatwaves and drought.

Connor Parker

The UK is twice as likely as usual to have a hot summer this year, the Met Office has forecast, as the driest spring in decades prompted warnings of heatwaves and droughts.

The Met Office's three-month outlook predicts that the chance of a hot summer is higher than normal, bringing an increased risk of heatwaves and heat-related impacts.

The outlook shows it is 2.3 times more likely than normal that the UK will be hot over meteorological summer, which runs from 1 June to 31 August.

The UK has enjoyed the sunniest spring on record, with some 630 hours of sunshine clocked up across the country between 1 March and 27 May, in what has also been the driest spring for more than a century.

Temperatures soared to 8C above the average for the time of year on Saturday 31 May – the last day of meteorological spring – ahead of a potentially hot summer season.

However the sunny weather has come at a cost, with reservoirs across the country at lower levels than usual.

The north of England has been hit the hardest, with a drought declared on 21 May in the North West.

How hot is a 'heatwave'?

Different groups have different definitions of a heatwave, but in the UK, most follow the Met Office's interpretation.

The Met Office defines a heatwave as “an extended period of hot weather relative to the expected conditions of the area at that time of year, which may be accompanied by high humidity”.

In the UK, the Met Office declares a heatwave when the daily temperature of a certain location meets or exceeds one of four temperature thresholds for a minimum of three days.

The lowest, covering Wales and Scotland, is 25C, and the highest, covering London, is 28C.

The longest official heatwave in the UK was in 1976, when a heatwave was declared during 15 consecutive days of hot weather.

The last official heatwave in the UK was in the summer of 2022 when there were three heatwaves declared in July and August.

Why is this summer going to be hotter than normal?

In a post alongside their three-month forecast, the Met Office said: “While the current three-month outlook shows an increased chance of a hot summer, the temperature signals for this summer are similar to those for recent years and consistent with our warming climate.

“The increased chance of hotter than average temperatures is not a guarantee of prolonged hot weather or heatwaves, but it does mean that heatwave conditions could be reached at times.

“However, it’s important to bear in mind that an increased chance of hot conditions could also reflect a mix of hot and cool days, warm nights, or less extreme levels of warmth rather than continual heatwave conditions specifically.”

The summers of 2018 and 2021-2023 were also predicted to be hot, with data showing it has been a decade since the last time a summer was predicted to be cool, in 2015.

The latest outlook also shows the levels of rainfall and wind speed for the next three months will likely be near average.