August in the Greek islands is shaped by one thing more than any other, and it is not the heat. It is the meltemi, the northerly wind that blows across the Aegean through midsummer. It keeps the islands cooler than the mainland, and it is also the reason ferry crossings get cancelled.
How strong it gets
The month opened with northerly winds of four to six on the Beaufort scale across the eastern seas, locally seven, and temporarily eight in the southern Aegean. Some stations recorded nine. On Evia, gusts reached 130 kilometres an hour at Karystos.
The wind typically strengthens through the afternoon and eases overnight, which is why morning crossings are the safer booking on a tight schedule.
Heat: eight degrees between island and mainland
On the same day, the mainland sat at 34 to 35 degrees with local peaks of 37, while the Cyclades did not pass 28 to 29. That gap is the meltemi at work. It is also the practical argument for putting the island section of a trip in the first half of August and the walking or sightseeing section later.
What the wind does to ferries
Two kinds of boat run the routes. Conventional ferries are slower but hold their schedule in rough seas. High-speed catamarans halve the journey and are the first to be cancelled when the wind rises; at force seven and above, small craft stay in port.
The consequence for planning is simple. If a ferry connects to a flight home, book the slow boat and leave a spare day. A cancelled catamaran in high season does not mean a later sailing, it can mean the next day.
What the rest of the month looks like
Forecasts point to the meltemi easing between roughly 4 and 10 August, with temperatures rising again as warmer air arrives from the western and south-western Mediterranean. Some models also expect dust carried up from Africa.
So the shape of the month is wind first, heat second. That order matters: the windy stretch is the one that threatens your schedule, the hot stretch is the one that threatens your afternoon plans.
Source: Travel News
