The fourth heatwave of the 2025 summer is now under way, with large parts of the UK expected to experience temperatures in excess of 30°C this week. According to the Met Office 234 areas across the UK saw official heatwave conditions on Monday, August 11, with the heat set to continue for the rest of the week. However while most of England is likely to experience these conditions data shows only four areas of Wales currently meet the Met Office's official definition of a heatwave. Forecasts show that Denbighshire , Wrexham , Monmouthshire , and Caerphilly are expected to hit temperatures in the 30s this week with Tuesday, August 12, predicted to be the hottest day, averaging at around 33°C across the board. Despite the potential for temperatures to climb above 25°C on Wednesday, August 13, in other parts of Wales the hot weather is not expected to last long enough to trigger heatwave conditions in most areas. You can see if your area is in heatwave conditions by typing your postcode into this interactive map: An official heatwave is declared when temperatures exceed a set threshold for three consecutive days but the thresholds vary across the UK. For much of Wales a heatwave is recorded if temperatures stay above 25°C for three days straight. Read the biggest stories in Wales first by signing up to our daily newsletter here . Meanwhile the heatwave is widespread across most of England excluding the northeast, Cumbria, and some coastal areas in the east and south. Scotland and Northern Ireland could see temperatures above 25°C briefly but not long enough to meet the three-day heatwave criteria. Only a handful of places, including Manchester, Trafford, and Warrington in the northwest and Rushmoor in Hampshire, saw heatwave conditions begin on Sunday, August 10. The remaining 230 areas, including the Welsh hotspots, entered heatwave conditions on Monday as temperatures exceeded their local thresholds. Here is a full list of areas now in heatwave conditions as of Monday, August 11: Day one of heatwave: Middlesbrough Darlington Halton Blackburn with Darwen Kingston upon Hull, City of North Lincolnshire York Derby Leicester Rutland Nottingham Herefordshire, County of Telford and Wrekin Stoke-on-Trent Bath and North East Somerset Bristol, City of South Gloucestershire Swindon Peterborough Luton Bracknell Forest West Berkshire Reading Slough Windsor and Maidenhead Wokingham Milton Keynes Cheshire East Cheshire West and Chester Shropshire Wiltshire Bedford Central Bedfordshire Buckinghamshire North Northamptonshire West Northamptonshire North Yorkshire Somerset Cambridge East Cambridgeshire Fenland Huntingdonshire South Cambridgeshire Amber Valley Bolsover Chesterfield Derbyshire Dales Erewash North East Derbyshire South Derbyshire Exeter Mid Devon North Devon Teignbridge Braintree Brentwood Chelmsford Colchester Epping Forest Harlow Uttlesford Cheltenham Cotswold Forest of Dean Gloucester Stroud Tewkesbury Basingstoke and Deane East Hampshire Hart Test Valley Winchester Broxbourne Dacorum Hertsmere North Hertfordshire Three Rivers Watford Ashford Canterbury Dartford Dover Gravesham Maidstone Sevenoaks Swale Tonbridge and Malling Tunbridge Wells Burnley Chorley Hyndburn Pendle Preston Ribble Valley Rossendale South Ribble West Lancashire Wyre Blaby Charnwood Harborough Hinckley and Bosworth Melton North West Leicestershire Oadby and Wigston Boston East Lindsey Lincoln North Kesteven South Holland South Kesteven West Lindsey Breckland Broadland King's Lynn and West Norfolk Norwich South Norfolk Ashfield Bassetlaw Broxtowe Gedling Mansfield Newark and Sherwood Rushcliffe Cherwell Oxford South Oxfordshire Vale of White Horse West Oxfordshire Cannock Chase East Staffordshire Lichfield Newcastle-under-Lyme South Staffordshire Stafford Staffordshire Moorlands Tamworth Babergh Ipswich Mid Suffolk Elmbridge Epsom and Ewell Guildford Runnymede Spelthorne Surrey Heath Waverley Woking North Warwickshire Nuneaton and Bedworth Rugby Stratford-on-Avon Warwick Crawley Bromsgrove Malvern Hills Redditch Worcester Wychavon Wyre Forest St Albans Welwyn Hatfield East Hertfordshire Stevenage West Suffolk Bolton Bury Oldham Rochdale Salford Stockport Tameside Wigan Knowsley Liverpool St. Helens Wirral Barnsley Doncaster Rotherham Sheffield Birmingham Coventry Dudley Sandwell Solihull Walsall Wolverhampton Bradford Calderdale Kirklees Leeds Wakefield City of London Barking and Dagenham Barnet Bexley Brent Bromley Camden Croydon Ealing Enfield Greenwich Hackney Hammersmith and Fulham Haringey Harrow Havering Hillingdon Hounslow Islington Kensington and Chelsea Kingston upon Thames Lambeth Lewisham Merton Newham Redbridge Richmond upon Thames Southwark Sutton Tower Hamlets Waltham Forest Wandsworth Westminster Denbighshire Wrexham Caerphilly Monmouthshire Day two of heatwave: Warrington Rushmoor Manchester Trafford