Red warning of extreme heat affecting London & South East England

Met Office sent this bulletin at 22-06-2026 10:35 AM BST
 
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Red warning for London & South East England
Extreme heat
Between 09:00 (UTC+1) on Wed 24 Jun 2026 and 21:00 (UTC+1) on Thu 25 Jun 2026

Headline

An exceptional spell of hot and humid weather is expected across this region, with impacts to the general population highly likely.

What to expect

  • Population-wide adverse health effects experienced, not limited to those most vulnerable to extreme heat, leading to serious illness or danger to life
  • Substantial changes in working practices and daily routines will be required
  • High risk of failure of heat-sensitive systems and equipment, with the loss of power and other essential services, such as water, electricity, gas or mobile phone services
  • Significantly more people visiting coastal areas, lakes and rivers, leading to an increased risk of water safety incidents
  • Delays on roads and road closures, along with delays and cancellations to rail and air travel, with significant welfare issues for those who experience even moderate delays

What should I do?

Issued: 10:30 (UTC+1) on Mon 22 Jun 2026

Further Details

During the heatwave expected to affect a large part of England and Wales this week, the highlighted area now looks increasingly likely to see a two to three day period where maximum temperatures in the shade exceed 37 Celsius, perhaps rising to 38 to 40 Celsius in some places. The heat will be accompanied by high humidity, exacerbating the potential for discomfort and health impacts, with very warm and humid night times also reducing the ability for people to recover overnight.

Significant disruption to daily life is likely and the public should take every effort to make precautions and adapt their daily routines where possible to cope with these levels of heat, which up to now have been extremely rare for the UK.

View full warning details and map view

Regions and local authorities affected

East Midlands

  • Northamptonshire

East of England

  • Bedford
  • Cambridgeshire
  • Central Bedfordshire
  • Essex
  • Hertfordshire
  • Luton
  • Thurrock

London & South East England

  • Bracknell Forest
  • Buckinghamshire
  • East Sussex
  • Greater London
  • Hampshire
  • Kent
  • Milton Keynes
  • Oxfordshire
  • Reading
  • Slough
  • Surrey
  • West Berkshire
  • West Sussex
  • Windsor and Maidenhead
  • Wokingham

South West England

  • Bath and North East Somerset
  • Bristol
  • Dorset
  • Gloucestershire
  • North Somerset
  • Somerset
  • South Gloucestershire
  • Swindon
  • Wiltshire

Wales

  • Blaenau Gwent
  • Bridgend
  • Caerphilly
  • Cardiff
  • Carmarthenshire
  • Merthyr Tydfil
  • Monmouthshire
  • Neath Port Talbot
  • Newport
  • Powys
  • Rhondda Cynon Taf
  • Swansea
  • Torfaen
  • Vale of Glamorgan

West Midlands

  • Herefordshire
  • Warwickshire
  • West Midlands Conurbation
  • Worcestershire