Seasonal low pressure is affecting the area.
Friday will be mainly fine but clouds that develop after midday are expected to lead to scattered showers in the afternoon, mainly in the mountains.
Temperatures will rise to around 35 C inland, around 30 C on the west coasts, around 32 C on the remaining coasts and around 25 C in the mountains.
Tonight will be mainly fine but there will intervals of increased low cloud on the west and north coasts.
Temperatures will fall to 22 C inland and on the north coasts, around 23 C on the remaining coasts and around 18 C in the mountains.
The weekend and Monday will be mainly fine, although there will be increased cloud in the mountains in the afternoons.
Temperatures will edge up on Saturday to close to average for the time of year, then rising a little more to above average.