The met service said storms are expected on Sunday, less than a week before the end of August.
Isolated showers or thunderstorms will affect mainly the mountains and eastern half of the island after noon during the day.
At night, it will be partly cloudy with the possibility of isolated showers in the west.
Temperatures will rise to 36C inland, 30C on the west and southwest coasts, around 33C on the remaining coastal areas and 26C in the higher mountains.
Temperatures will drop to around 21C inland at night, 24C on the west and southwest coasts, around 22C on the rest of the coast and 18C in the mountainous areas.
Isolated showers and storms are also expected on Monday and Tuesday in the eastern half of the island.
On Wednesday, the weather will be mostly clear. Temperature will remain in similar levels for the next three days.