A four-week-old baby was among 10 children admitted to one hospital in the region with sunburn since the period of hot weather began.
The oldest patient was 14, according to the Queen Victoria Hospital in East Grinstead, West Sussex.
Six of the 10 children admitted needed specialist treatment after being referred to the unit from other hospitals because of the severity of their burns.
A spokesman for the hospital said the extent of the burns ranged from 0.5% to 4% of the body surface area. All the children came from the South East, from Chichester in West Sussex to Swanley in Kent.
The sun at this time of year is very strong and children can get burnt very quickly.
The children we've treated over the last few weeks have been referred to our unit because their burns have been so severe they have required specialist treatment.