The meteorological department has issued a yellow weather warning for extreme maximum temperatures inland on Friday, with temperatures expected to reach around 40C.

The warning will be in effect from 2pm until 4.30pm.

Friday will be mostly clear, although locally increased cloud is expected to develop as the day progresses. There is a chance of isolated showers over the mountains during the afternoon.

Winds will initially be light and variable or onshore at around force 3 Beaufort, gradually becoming southwesterly to northwesterly at force 3 to 4, strengthening to force 4 to 5 along the coast during the afternoon. The sea will be calm to slightly rough, becoming temporarily slightly rough on windward coasts later in the day.

Temperatures will climb to around 40C inland, 32C on the west and southwest coasts, 34C along the remaining coastal areas and around 29C in the higher mountains.

Overnight, conditions will remain mostly clear, with increased low cloud expected to develop later, mainly along the coast. During the early hours of Saturday, patchy mist or fog may form in some southern and eastern areas.

Winds will become light downslope at around force 3 Beaufort, while the sea will remain calm to slightly rough. Temperatures will fall to around 24C inland and along the coast, and 20C in the higher mountains.

The weather is expected to remain mostly clear on Saturday, Sunday and Monday, with periods of increased cloud. Afternoon cloud developing over the mountains may bring isolated showers or even thunderstorms.

Temperatures are not expected to change significantly through Monday and will remain above average for the time of year.