Friday will be mainly fine with increased clouds at intervals from midday on, mainly in the mountains.
Temperatures will be 39 C inland around 31 C on the west coast and in the mountains and around 34 C on the remaining coasts.
Tonight will be mainly fine, although there will be patchy fog and low cloud locally.
Temperatures will fall to 22 C inland and on the south and east coasts, around 21 C on the west and north coasts and around 18 C in the mountains.
The weekend and Monday will be mainly fine.
Temperatures will remain basically unchanged, a little above average for the time of year.