Weak low pressure is affecting the area and there will be dust in the atmosphere at intervals until Friday, the met office said in its early morning weather forecast.
Wednesday will be partly cloudy with the possibility of light showers. Temperatures will be 30 C inland and on the east coast, 27 C on the south coast, 24 C on the west and north coasts and 19 C in the mountains.
Thursday will be partly cloudy with the possibility of localised light showers.
Friday will start off mainly fine but clouds will develop in the afternoon which may lead to isolated showers or thunderstorms.
Temperatures will edge down on Thursday and Friday to a little below average for the time of year.
Saturday will start off fine but there will be increased cloud in the afternoon.
Temperatures will edge up.