The UK Health Security Agency (UKHSA) has issued a yellow heat health alert for regions including London, the South East and East Midlands as temperatures are set to soar to 30C - full list of areas affected11:00, 17 Jun 2026Updated 11:00, 17 Jun 2026A sizzling heatwave is set to sweep across large swathes of the UK, with scorching temperatures making a dramatic return.‌Following a spell of cooler, wet weather, summer is poised to make a fierce comeback this weekend, with mercury levels expected to soar to as high as 30C according to the Met Office.‌The UK Health Security Agency (UKHSA) has issued a stark warning of "greater risk to life of vulnerable people" as a new yellow heat health alert is due to come into effect.‌The alert runs from 3pm on Wednesday, June 17, until 8pm on Monday, June 22, with further concerns including greater demand on healthcare services from vulnerable individuals, dangerously warm indoor environments, and a heightened risk of water-related incidents.The UKHSA confirmed the warning will cover London, the South East, East of England and the East Midlands.The Met Office has cautioned that temperatures across the South East could hit heatwave levels by the weekend.‌"Friday is likely to see very warm, locally hot conditions for south-east and some eastern areas of England, with higher humidity and the chance of a few thunderstorms," a UKHSA spokesperson said on Monday, June 15."There is considerable uncertainty for the duration of the very warm conditions however, as a weak weather front moving east into Saturday may bring slightly lower temperatures and fresher conditions."However, there is the potential that the weather front stalls toward the South East allowing very warm or hot conditions to linger across, or near to the far south or South East, perhaps then becoming more extensive again into the following week."‌Met Office meteorologist Jonathan Vautrey warned that climbing temperatures and rising humidity are likely to be accompanied by cloudy skies for much of the country."By Friday there is potential for 30C across parts of south-eastern England," Mr Vautrey said.He went on: "The exact detail of the temperatures is going to be dependent on cloud amounts, because, whilst it is going to be warmer this coming week, there's actually going to be a reasonable amount of cloud around at times as well – so it's not going to be sort of wall to wall sunshine every day.‌"But those temperatures are going to be rising nonetheless and, with that, it's also going to be increasingly humid this time around."So I think people will certainly be noticing how muggy it starts to feel during the second half of this weekend, and some quite uncomfortable nights for sleeping well, with overnight temperatures in the high teens across south-eastern areas of England."Mr Vautrey also noted that the West Midlands, parts of the West Country and areas of Wales are expected to see warm temperatures reaching the mid-teens by the close of the week. Meanwhile, Scotland and Northern Ireland are set to experience considerably cloudier conditions and rainfall throughout the week, with temperatures in those areas of the UK not expected to exceed 20C to 21C.Article continues belowUK regions covered by the heat health alert:LondonSouth EastEast of EnglandEast Midlands