Temperatures could break the UK's June record this weekend, as an amber heat health alert comes into force across southern England and forecasters warn the mercury may reach 34C or higher on Monday.
The UK Health Security Agency (UKHSA) has issued amber alerts covering London, the east, south-east and south-west of England, valid until 20:00 BST on Tuesday. Yellow alerts are in place for the East and West Midlands. The warnings suggest a likely increase in deaths, especially among those aged over 65 or with long-term health conditions.
“Amber heat health alerts issued as temperatures could reach 34C and break UK June record.”
Met Office meteorologist Honor Criswick said this heatwave would feel different from the one in May. "It's a bit different to the last heatwave, because last time the humidity wasn't as high, whereas this time the humidity is quite a bit higher," she said. "It's just going to make it feel that bit muggier and that bit more humid during the day and overnight as well." She added that the high humidity could spark thunderstorms, particularly across central, southern and south-east England, with "intense, heavy downpours for a time".
Friday is expected to be the first very hot day, with East Anglia potentially reaching 32C. Temperatures are forecast to hit 32C in the south and south-east on Sunday, and could climb to 33C on Monday. Deputy Chief Forecaster Gregory Wolverson said: "There is currently a 40% chance of exceeding the current UK June maximum temperature record of 35.6°C, set in 1957 and 1976. There is also a lower chance of exceeding the June maximum temperature record for Wales."
Met Office meteorologist Alex Deakin described the forecast as "pretty unusual even for the middle part of June". The heat is being driven by a large, static area of high pressure over western Europe, creating a "heat dome" that traps warm air beneath it. Temperatures across Spain, France and Germany are set to rise into the mid-to-high 30s, with Paris potentially exceeding 40C on Sunday.
The hot weather is expected to cause disruption on the railways, with speed restrictions possible as tracks could buckle in the heat. National Rail advised passengers to carry water and use free refill stations at larger stations. On the roads, drivers were urged to remove items such as medications, aerosols, carbonated drinks and battery-powered gadgets from parked cars, as stationary vehicles can become dangerously hot rapidly. Official guidance stressed that infants, children, older people and animals should never be left alone in vehicles.
While southern England swelters, Scotland and Northern Ireland will see outbreaks of heavy rain, with temperatures closer to the seasonal average at around 17-24C. Parts of northern England and Wales will also see wet weather.
There is uncertainty about the forecast into the middle of next week, but many computer weather models suggest the heat will linger, especially in the south. It is likely that some places will meet their official heatwave criteria — three consecutive days above a threshold that varies from 25 to 28C across the UK.