Seasonal low pressure is affecting the area and Thursday will be mainly fine although there will be increased local cloud at intervals.
Temperatures will rise to 38 C inland, around 32 C on the east and south coasts and around 30 C on the remaining coasts and in the mountains.
Thursday night will be mainly fine. Locally and mainly at dawn low cloud or patchy fog is forecast.
Temperatures will fall to 21 C inland, around 22 C on the south and east coasts, around 20 C on remaining coasts and 16 C in the mountains.
Friday, Saturday and Sunday will be mainly fine initially but clouds that develop from midday on may lead to scattered rain or isolated thunderstorms, mainly in the mountains and inland.
Temperatures are expected to remain at about the same levels, which are about average for the time of year.