The met service on Wednesday issued a yellow warning for extreme high temperatures expected on Thursday.
The service said the maximum temperature inland is expected to reach 41 degrees Celsius between 11am and 5pm.
Coastal temperatures will reach 33C in the west and around 36 in the other seaside areas. In the higher areas it will be 31C, the Met said.
It urged the public to take all precautions, especially vulnerable groups like the elderly and young children.