Key keywords: UK bank holiday heatwave 2024, Met Office heat alert, UKHSA heat health advice, bank holiday weekend high temperatures, southern UK peak heat, post-heatwave thundery showers, UK summer weather forecast, UK bank holiday travel tips The UK Met Office has confirmed that a prolonged period of unseasonably warm weather will escalate into an official heatwave over the late May bank holiday weekend, bringing record-breaking temperatures for the time of year to most parts of the country. Temperatures have already climbed to 24-26°C across most of England and Wales since Wednesday, with parts of London recording 27°C on Thursday afternoon, marking the warmest spell of 2024 so far. The mercury is set to rise steadily through Friday, before peaking on Saturday and Sunday, when inland areas of southeast England, East Anglia and Greater London could see highs of 32°C, 8°C above the long-term average for late May. Even northern regions will see unseasonable warmth, with highs of 27°C expected across lowland Scotland, 28°C in northern England and 26°C across most of Northern Ireland, making this bank holiday one of the warmest on record for the UK as a whole. In response to the expected heat, the Met Office has issued a yellow heat health alert covering all of England, most of Wales and southern Scotland, active from 8am on Saturday 25 May to 6pm on Monday 27 May. The UK Health Security Agency (UKHSA) has also published guidance for vulnerable groups, urging people aged over 65, children under 5, and those with pre-existing heart or respiratory conditions to stay hydrated, avoid direct sunlight between 11am and 3pm, and keep living spaces well ventilated. Officials have also warned against open fires in rural areas, as the extended dry spell has left grassland and woodland tinder-dry, raising the risk of wildfires across most of the UK. For the estimated 16 million Britons planning to travel over the bank holiday weekend, transport authorities have issued warnings of potential disruption. Network Rail has said it will implement speed restrictions on some rail lines in southern England if track temperatures exceed 50°C, to avoid rail buckling, while major roads leading to coastal resorts, national parks and popular holiday destinations are expected to see heavy congestion from Friday afternoon onwards. Coastguard teams have also increased staffing levels at popular beaches, urging visitors to follow water safety guidance and avoid swimming in unpatrolled areas, as warm weather is expected to drive record numbers of people to the coast. The heatwave is expected to break on Monday evening, when a band of thundery showers will move in from the north, bringing heavy rain, lightning and occasional hail to parts of Scotland and northern England. The unsettled weather will spread southwards on Tuesday, bringing temperatures back down to the seasonal average of 18-21°C across most of the country by the middle of next week.