Will there be a heatwave in the UK in 2023? Latest forecast

After an unsettled summer, many are wondering whether there will be a heatwave in the UK and how warm it's predicted to get

A woman sunbathing in a dry field
(Image credit: Getty Images)

As September arrives temperatures have increased, and many are asking if there will be a heatwave in the UK...

Last year saw record temperatures in the UK, with some areas experiencing highs of 40C in what became a sweltering summer - and the warmest on record. But 2023 has been a different story, and despite temperatures in Italy, Spain and Greece soaring, rain and cloud in the UK has left many wondering why the weather is so bad.

However, back in June, the UK experienced a spell of exceptionally warm weather too, with many of us frantically looking for ways to keep the house cool and wondering if you should keep windows closed in hot weather. Now that September has arrived, it looks like the sun has returned, prompting last-minute searches for the best sun creams and the best paddling pools to make the most of the warm spell.

Will there be a heatwave in the UK in 2023?

Yes, some areas of the UK are expected to experience heatwave temperatures, according to Met Office forecasters. This is because the jet stream - which is a core of strong winds above the earth's surface - is moving north, bringing high pressure to the UK. 

Met Office Deputy Chief Meteorologist, Chris Bulmer, said: "As high pressure becomes established from this weekend, fine and settled conditions will develop and along with this we will see a rise in temperature across most parts of the UK next week. Many places can expect to see maximum temperatures rise to 25C or above for several days, which would bring some locations into the realm of heatwave conditions."

June saw temperatures soar above 30C in the UK, and has been confirmed as the hottest on record. And Northern Ireland has already experienced a heatwave this year, after temperatures exceeded 25C in several areas for three consecutive days.

The Met Office said, "According to provisional Met Office figures, the average mean temperature of 15.8C for June 2023 in the UK is the highest in a series since 1884, with England, Scotland, Wales and Northern Ireland also reporting their respective warmest June on record."

This is partly due to the return of the 'El Niño' climate phenomenon, making it likely that the world will exceed 1.5C of warming. The hottest year in recorded history, 2016, was also driven by a major El Niño - which is a term used to describe the warming of sea surface temperature that occurs every few years, usually in the Pacific.

What is a heatwave?

The Met Office explains that in order for a weather event to be an official heatwave, the location must record "a period of at least three consecutive days with daily maximum temperatures meeting or exceeding the heatwave temperature threshold." 

In the UK, these thresholds vary by area - which is why Northern Ireland experienced a heatwave earlier in the year, but other areas with a higher threshold have not.

For example, a heatwave in London must reach a temperature of above 28C, while in Scotland the threshold is 25C. With the mercury hitting above 30C in London on Sunday 11 June, the capital has seen heatwave-level temperatures, but these did not last for the required three consecutive days.

See more

When is the next heatwave in the UK?

The heatwave in the UK is forecast for the first week of September. Temperatures up to 30C are predicted in some areas of the UK, with the Met Office forecast reading, "Mostly dry with very warm or hot sunshine," for the week ahead.

And it looks like the warm spell could last for the remainder of the month, as the Met Office has said in their long-range forecast, "It is possible that the end of the month may be slightly drier than usual as there are indications for more high pressure affecting the country than normal."

The weather service adds that while periods of rain of showers are also possible, "Temperatures are generally likely to be above average for the time of year, and there is a chance that parts of the country may see some very warm spells."

Where is there going to be a heatwave in the UK?

The highest temperatures are likely to be in the south and east of England, according to meteorologist Chris Bulmer. He added: "While some areas may just miss out on the actual definition, regardless of thresholds, many areas will enjoy a fine period of weather with plenty of sunshine and temperatures are likely to be the highest for many since June or early July." 

The current forecast predicts temperatures as high as 30C in London, with Cardiff, Manchester and Glasgow all predicted to experience temperatures in the mid to high twenties. 

The hottest temperature of the year so far was recorded in Surrey. A temperature of 32.2C was recorded in Chertsey on Sunday 11 June, and it was the first time since August last year that temperatures had gone above 30C in the UK. 

On 25 June, the same temperature was recorded in Coningsby, Lincolnshire, making it the joint hottest day of the year so far.

And with many climate scientists anticipating the return of the El Niño, it's not just the UK that has experienced hotter than average temperatures this year, as the climate phenomenon affects the entire globe.

See more

Will it be a hot summer in the UK in 2023?

The Met Office has predicted that 2023 will be hotter than 2022 overall and one of the warmest years on record. Temperatures are predicted to rise by between 1.08C and 1.32C, which will mark the 10th year in a row that global temperatures will reach at least 1C above average.

This has been attributed to both climate change and the ending of the weather pattern known as La Niña, after three years of cooler-than-average sea temperatures in the Pacific Ocean causing lowered average global temperatures.

Across the world, climate records are already being broken in 2023, with daily high temperatures breaking records in South Florida and Arizona in the US. Meanwhile, Monday 3 July was officially the hottest day ever recorded globally, according to data from the US National Centers for Environmental Prediction.

The average global temperature reached 17.01C, surpassing the August 2016 record of 16.92C.

More recently, Italy has experienced its third heatwave of the summer, and holidaymakers were evacuated from Rhodes as the Greek Islands battled wildfires caused by hot weather.

In fact, according to a report from Reuters, the UN has estimated that July 2023 was the hottest month - in terms of the average global temperature - in recorded history.

UN secretary-general António Guterres has said, "We don't have to wait for the end of the month to know this. Short of a mini-Ice Age over the next days, July 2023 will shatter records across the board."

How hot are temperatures predicted to get in the UK?

It has been suggested that El Niño could see global warming reach the crucial barrier of a 1.5C rise. However, temperatures in the UK have been close to average this summer.

Last summer, the UK had one of its hottest summers on record, with temperatures exceeding 40C for the first time. The Met Office issued a red weather warning for extreme heat, and drought was officially declared in some areas of the country.

Peak temperatures in the UK are usually recorded in August, when the average maximum temperature is 19.31°C, with the average minimum temperature recorded as 10.97°C.

Meanwhile, September is usually a cooler month, will the average maximum temperature recorded as 16.85°C and the average minimum temperature 9.04°C.

Average temperatures in the UK in September by country:

  • England - Maximum 18.14°C, minimum 9.71°C
  • Scotland - Maximum 14.78°C, minimum 7.88°C
  • Wales - Maximum 16.87°C, minimum 9.30°C
  • Northern Ireland - Maximum 16.29°C, minimum 8.89°C

If you're heading on holiday abroad this summer, you might want to check out our guides on the best sunscreens for your face and the best sunscreens for kids and toddlers. Or if it's a staycation for your family, beat the wet weather with these 72 things to do with kids and these easy crafts for kids to keep them entertained if it's a washout.

Ellie Hutchings
Family News Editor

Ellie is GoodtoKnow’s Family News Editor and covers all the latest trends in the parenting world - from relationship advice and baby names to wellbeing and self-care ideas for busy mums. Ellie is also an NCTJ-qualified journalist and has a distinction in MA Magazine Journalism from Nottingham Trent University and a first-class degree in Journalism from Cardiff University. Previously, Ellie has worked with BBC Good Food, The Big Issue, and the Nottingham Post, as well as freelancing as an arts and entertainment writer alongside her studies. When she’s not got her nose in a book, you’ll probably find Ellie jogging around her local park, indulging in an insta-worthy restaurant, or watching Netflix’s newest true crime documentary.