Seasonal low pressure is affecting the area and Friday will be initially fine, but with increased cloud in the afternoon at intervals, mainly in the mountains.
Temperatures will be 38 C inland, around 32 C on the west coasts, around 34 C on the remaining coasts and 30 C in the mountains.
Tonight will be mainly fine with patchy fog and low cloud possible in the early hours.
Temperatures will drop to 21 C inland, 23 C on the coasts and 17 C in the mountains.
The weekend and Monday will be mainly fine, with increased cloud at intervals in the mountains.
Temperatures will edge up on Saturday, remaining at the same levels on Sunday before edging down again on Monday to a little above average for the time of year.