The Met Office issued a yellow alert on Wednesday with temperatures set to rise to 40 degrees centigrade inland, remaining at the same levels on Thursday and Friday.
It said the extreme high temperature warning applied from 11 am to 4 pm.
“Be aware that high temperatures are expected. Some health risks amongst vulnerable people e.g. the elderly and very young are possible,” the Met Office said on its website.
According to Wednesday’s forecast the weather will be mainly fine with temperatures expected to rise to 40 C inland, 32 C on the western shores, around 35 on the remaining shores and 30 in the mountains.
Tonight temperatures will be 25 inland, the south and east shores , around 24 in the west and north shores and 21 in the mountains.
The weather will remain fine on Thursday, Friday and Saturday. Temperatures will remain unchanged on Thursday and Friday and record a small drop on Saturday.