Why this week's UK heatwave finally broke the 'June 13th enigma'
A more mysterious weather phenomenon, which has held for 150 years, was finally broken this week.
Temperatures climbed to over 30C on Tuesday, with the Met Office officially declaring parts of the UK are in a heatwave.
A swathe of the UK stretching from the north west to the south east of England exceeded the threshold for a heatwave.
Temperatures have soared in recent days, hitting 32.2C in Chertsey, Surrey, on Saturday 10 June, the highest recorded so far this year.
According to the Met Office, a heatwave is defined as three consecutive days with daily maximum temperatures meeting or exceeding the heatwave temperature threshold.
The threshold varies in each county.
But amid the news of heatwaves, a more mysterious phenomenon, known as the ‘June 13th enigma’, was broken on Tuesday.
What is the June 13th enigma?
According to data stretching back more than 150 years, 13 June has traditionally been cooler than any other day in summer and temperatures of 30C or above had never previously been recorded.
The statistical quirk has meant weather-watchers eagerly monitoring the temperatures on the date every year to see if the elusive 30C will finally be reached.
On Tuesday this week, temperatures finally broke the barrier – meaning every day of meteorological summer has now had a temperature of at least 30C.
Met Office spokesman Ollie Claydon said: “It's very strange, but 13 June is the only day of summer never to have recorded a temperature above 30C in records that go back to at least 1870.
“But it has now.
Did you know...❓
The 13th of June was the only date in meteorological summer since records began, that had never reached 30°C or above anywhere in the UK...Until today!
Here are todays maximum temperatures 👇 pic.twitter.com/a9Cz6HjtYV— Met Office (@metoffice) June 13, 2023
What were the temperatures on 13 June?
Some areas experienced hotter weather than Ibiza on 13 June, where temperatures on the Balearic island reached 26C.
Four weather stations in the UK broke the 30C barrier – including in Porthmadog, Wales, where the 30.8C reached meant it was the hottest part of the country.
Bridgefoot in Cumbria and Hurn in Dorset both saw temperatures of 30.1C, while Herstmonceux in East Sussex reached exactly 30C.
Watch: Week of sunshine predicted across the UK
Is there a link between heatwaves and climate change?
A Met Office study carried out in 2018 said human-induced climate change made record-breaking high temperatures 30 times more likely than they would be naturally.
Dr Nikolaos , a Met Office scientist, said in December 2018: “Our models show that there is now about a 12% chance of summer average temperatures being as high as the UK experienced in summer 2018. This compares with a less than half per cent chance we’d expect in a natural climate.”
The highest ever UK temperature of 40.3C was recorded on 19 July last year at Coningsby in Lincolnshire.
Will the warm weather continue?
Warm temperatures are forecast to remain across the UK for the rest of the week, the Met Office said – but the mercury is likely to remain lower than recent hot conditions.
The forecaster said temperatures in the mid-to-high 20s is expected for much of England over the next few days with London expected to reach a high of 28C on Wednesday and Manchester likely to see a top of 27C.
The mercury could also push 28C in Cardiff in the afternoon, while temperatures should be slightly cooler across Scotland, Ireland and Northern Ireland.
Met Office spokesman Stephen Dixon said: “The heat is set to drop slightly in coming days.
“London might not meet heatwave criteria, for example, but there’s a good deal of dry, fine, sunny weather to be had this week with temperatures remaining well above average.
“Into the weekend there should be a fair amount of dry weather, with temperatures remaining warm for many, although also humid and warm overnight.”
Thursday may see thunder in western areas of Northern Ireland and parts of Wales, with a risk of showers on Friday, Dixon added.
