Seasonal low pressure is affecting the area.
Wednesday will be mainly fine but there will be increased cloud in the afternoon, mainly in the mountains.
Temperatures will be 39 C inland, around 33 C on the east and south coasts and around 30 C on the remaining coasts and in the mountains.
Tonight will be mainly fine but early in the morning there may be patchy cloud or low cloud.
Temperatures will fall to 21 C inland and on the coasts and around 17 C in the mountains.
Thursday, Friday and Saturday will be mainly fine but in the afternoon there will be increased cloud that may lead to scattered showers or isolated thunderstorms, mainly in the mountains and inland.
Temperatures will remain at the same levels on Thursday and Friday and will edge up a little on Saturday to a little above average for the time of year.