The mercury is set to rocket to 32C today with the East Midlands, West Midlands, East of England, London, South East and South West under amber heat-health alerts.
Forecasters issued the alert which will cover London, the East Midlands, the South East, the South West and the East of England, and is set to remain in place until 6pm tomorrow.
The three sisters had vanished after a three-hour visit with their father Travis Decker, sparking a days-long manhunt before their bodies were located on Monday.