On 8 July, the Met Office issued a heat-health alert warning that there was a 90% probability of level 3 alert criteria being met in parts of England on 9 July. On 12 July, the Met Office issued an
amber extreme-heat warning for 17 July, which was extended from 17 to 19 July. It was stated that the high temperatures could extend into the following week. By 13 July, the water levels at the
Thruscross Reservoir fell low enough to reveal the ruins of West End, a village which was flooded when the reservoir was built in 1966. On 15 July, the
UKHSA increased the Heatwave Alert Level to 4, "illness and death occurring among the fit and healthy – and not just in high-risk groups". The Met Office issued its first ever red extreme-heat warning after there were forecasts of over in some parts of England, and a
national emergency was declared. The warning was in place from 18 to 19 July, with most of England being affected. The amber extreme-heat warning was extended to cover
Cornwall, west Wales and parts of southern Scotland. A number of schools announced they would either close or allow pupils to wear
PE kit in place of their
school uniform on the hottest days. On 17 July, the first day of the amber warning, the highest temperature recorded was in
Hawarden, Wales. The highest temperature in England was in
Nantwich, and the highest in Scotland was in
Auchincruive. Northern Ireland reached in
Armagh. On 18 July, the first day of the red warning, temperatures reached in
Santon Downham,
Suffolk. Wales broke its record for the highest recorded temperature, with recorded in
Hawarden. The
Channel Islands had a new record temperature as was recorded in
St Helier. The highest temperature in Scotland was in
Aboyne, and the highest in Northern Ireland was in
Derrylin. Cornwall reached in
Bude, breaking the county's record of set during the
1976 British Isles heatwave. Between 18 and 19 July, the United Kingdom experienced its highest recorded minimum nighttime temperature, at at Shirburn Model Farm,
Oxfordshire. This is an increase of 2.9 °C from the previous record, set in
Brighton in August 1990. Temperatures in many other parts of the country did not fall below , giving the UK its warmest
tropical night on record. On 19 July, a temperature of was recorded at
Coningsby,
Lincolnshire, the hottest temperature ever recorded in the United Kingdom. Before that day, the previous record of was recorded in Cambridge during the
2019 European heatwaves. The Met Office reported that this record was broken at 46 stations across England on 19 July, six of which recorded temperatures at or above 40 °C, stating that the "extreme heat was far more intense and widespread than previous comparable heatwaves". Many locations broke their previous record temperatures by large margins; for example,
Durham reached , breaking its previous record of by 4.0 °C. Scotland had its highest temperature ever after was recorded at
Charterhall, British minister
Kit Malthouse told Parliament that at least 13 people died in water-related incidents during the heatwave, and that at least 41 properties were destroyed in London and more than a dozen elsewhere in Britain.
Impact Transport , London, to prevent heat damage
Network Rail announced that the
East Coast Main Line would close on most of the day on 19 July, for all stations between and and . Many
train operating companies, including
Greater Anglia,
Great Western Railway and
London North Eastern Railway, introduced amended timetables, imposing speed restrictions on their trains to avoid
track buckling.
Transport for London urged people to make only essential journeys on 18 and 19 July. On 18 July, all flights at
Luton Airport were suspended after the high temperatures led to a surface defect on the runway. The
RAF halted all flights in and out of
Brize Norton, the UK's largest RAF station, because "the runway melted". The rail temperature in
Suffolk hit , which was the highest-ever recorded in the UK. On 19 July, Network Rail issued a "do not travel" warning ahead of the extreme temperatures. No services ran into or out of London King's Cross all day, and no
Thameslink or
Great Northern services were running north of London.
East Midlands Railway was running very limited services between , , , and , which stopped entirely during the hottest part of the day. The East Coast Main Line south of York was closed, as well as the
Sheffield Supertram network. Among these roads was the
A14, which was closed westbound between J36 and J35 for hours after a part of the road "rose and then cracked". Part of the
A11 was closed both ways after there was damage to one of the lanes.
Retail A corner shop in
Scunthorpe lost around £1,000 worth of goods when its entire stock of chocolate melted during the heatwave. Major supermarkets in London reported having sold out of bottled water, ice cream, and
ice lollies during the heatwave, and increased sales of paddling pools and burgers.
Waitrose reported a 36 per cent year on year increase in the sales of ice cream. Luxury chocolate products retailer,
Hotel Chocolat, suspended their delivery service because of the hot weather. Low rainfall and prolonged sunshine in Kent, Herefordshire, Lancashire, and Norfolk provided excellent growing conditions, promoting the strong growth of ripe sweet berries.
Utilities On 25 July,
Bloomberg News reported that South East London had narrowly avoided experiencing a
blackout on 20 July, after the increase in demand for electricity caused by the hot weather. It was prevented by the
National Grid purchasing electricity from Belgium at the highest price the UK had ever paid. They were reported to have paid £9,724 per megawatt hour, 5,000% more than the typical price.
Aftermath Weather forecasters from the BBC, Met Office and the
Royal Meteorological Society were subjected to online abuse and questioned validity over their coverage of the heatwave, most prompted by reports that linked it to climate change. on 19 July, the hottest day of the heatwave, as seen from the
University of Kent,
Canterbury. On 19 July, steep
lapse rates in the mid troposphere associated with the plume of hot air led to the development of a line of elevated
dry thunderstorms that initiated along a
cold front ahead of an approaching upper
trough, affecting southern England. These storms produced very little precipitation, with accumulations of just 1-2mm in places. This, combined with frequent cloud-to-ground
lightning and dry vegetation, created additional fire hazards. Several thousand lightning strikes were detected, causing at least one residential fire. On 3 August,
Marks and Spencer announced that it would stop selling
disposable barbecues "to help protect open spaces and reduce the risk of fires". Their decision followed calls by London Fire Brigade for retailers to stop selling them. Along with
Aldi and
Waitrose, who stopped in March over concern about the impact of their use on the environment,
Sainsbury's and
Tesco joined the list of supermarkets to stop selling disposable barbecues on 11 August, and were followed by
Morrisons and the
Co-op the next day. == August heatwave ==