An extreme heat weather warning has been issued for large parts of the country for the first time ever by the the Met Office.
The warning will be in place until Thursday evening—when temperatures are expected to peak.
The Met Office's extreme heat warning means that people should expect:
Adverse health effects are likely to be experienced by those vulnerable to extreme heat
The wider population are likely to experience some adverse health effects including sunburn or heat exhaustion (dehydration, nausea, fatigue) and other heat related illnesses
More people are likely to visit coastal areas, lakes and rivers leading to an increased risk of water safety incidents
Some changes in working practices and daily routines likely to be required
An increased chance that some heat-sensitive systems and equipment may fail, leading to power cuts and the loss of other services to some homes and businesses
Some delays to road, rail and air travel are possible, with potential for welfare issues for those who experience prolonged delays
The warning covers the following local authorities:
Blaenau Gwent
Pen-y-bont ar Ogwr
Caerffili
Caerdydd
Sir Gâr
Ceredigion
Merthyr Tudful
Sir Fynwy
Castell-nedd Port Talbot
Casnewydd
Sir Benfro
Powys
Rhondda Cynon Taf
Abertawe
Torfaen
Bro Morgannwg