An amber heat-health alert has been issued for all regions in England as the UK could record a new high for the warmest day of the year on Thursday.
Eastern parts of Wales, the Midlands and the south-east of England could reach 30C, which would break the current record for 2025 of 29.4C set days ago in Santon Downham in Suffolk.
UV and pollen levels are also expected to climb alongside temperatures.
The amber alert issued by the UK Health Security Agency is in force from 12pm on Thursday until 9am on Monday.
It warns “significant impacts are likely” across health and social care services because of high temperatures, including a rise in deaths – particularly among those aged 65 and over or people with health conditions.
An official heatwave is recorded when areas reach a certain temperature for three consecutive days, with thresholds varying from 25C to 28C in different parts of the UK.
Met Office meteorologist Clare Nasir said: “High UV levels and high levels of pollen as well.
“Winds remain fairly light and a warmer day all round across the east coast as temperatures arrive around 24C, but 28C for Liverpool, Leeds, 23C for Glasgow and Edinburgh, Belfast coming in around 24C, 28C likely across Bristol as well as Cardiff.
“But for east Wales, the Midlands, down towards the South East we could see temperatures peaking around 30C, so feeling hot here.”
A number of charities have issued warnings about the potential risks of hotter weather.
St John Ambulance urged the public to familiarise themselves with the signs of heat exhaustion and heat stroke and to learn how to respond.
It comes after a survey of 1,002 adults in England revealed more than half do not know the difference between “life-threatening” heat stroke, which requires a 999 call, and heat exhaustion, which can be treated by cooling and hydrating a patient.
The British Heart Foundation is encouraging people with heart conditions to take precautions such as staying cool and keeping hydrated to minimise potential health risks during a heatwave, saying the heat can put extra strain on the heart.
Age UK urged people to check in on older relatives, friends, and neighbours to see if they need anything and to make sure they are not feeling overwhelmed by the excessive heat.
Cloud and patchy rain will move northwards across northwest Scotland this afternoon, with widely sunny skies across the rest of the country ☀️
— Met Office (@metoffice) June 19, 2025
Very warm or hot, and feeling humid in the west later 🥵 pic.twitter.com/66U2qC31vy
Dementia UK issued advice and tips on how to support a loved one with dementia in the heat, including keeping hydrated; staying cool with appropriate clothing; keeping the person out of the heat; cooling the person down by avoiding hot drinks, alcohol and caffeine; and keeping the home environment cool.
RAC breakdown spokeswoman person Alice Simpson warned drivers should “take every precaution” in the heat.
“When temperatures soar, vehicle breakdowns usually do the same,” she said.
“One of the biggest risks is an increase in cars overheating, especially when sat in queues of traffic with no shade.”
Ms Simpson urged drivers to check their coolant levels and any air conditioning systems that are not working properly, and to take plenty of water and snacks on the road.
