Temperatures are likely to rise into the mid 30s Celsius in south east London (Bexley, Bromley, Greenwich, Lambeth, Lewisham, Southwark), and across the London region.
The NHS has shared tips for staying well.
If you are planning to spend time outside, please take care and follow these NHS.UK guidelines for applying sunscreen and sun safety. Older people, young children and people with long term health conditions may need help keeping cool. Learn more about checking for signs of heat exhaustion.
For the latest updates on weather alerts in your area, head to www.metoffice.gov.uk.