The Met Office has issued a new yellow weather warning for extreme high temperatures, lasting from noon on Monday until 6am on Tuesday.
Vulnerable populations, children, and the elderly, are urged to take precautions.
On Monday the weather will be mostly clear. Winds will be north-easterly to south-easterly in the morning, weak to moderate, 3 to 4 Beaufort becoming south-westerly to north-westerly in the late afternoon. The sea will be somewhat turbulent. Temperatures will rise to 39C inland, 34C in the south, east and north coasts and 32C on the west coast and higher mountains.
On Monday night, the weather will be mostly clear. Temperatures will drop to 26C inland, on the west and north coasts, 24C on the south and east coasts, and 21C in the higher mountains.
On Tuesday, Wednesday and Thursday, the weather will be mostly clear.
The temperature is not expected to change significantly until Thursday, remaining above the average for the season.