The Etesian winds
The Meltemi wind was known by the old Greek as the Etesian northern winds, and results from a high pressure system (>1025) laying over the Balkan/Hungary area and a relatively low pressure (<1010) system over Turkey. Although this katabatic wind can bring about harsh sailing conditions it also provides cooling, low humidity and good visibility. Furthermore, it can be characterized as one of the few Mediterranean winds that do not necessarily die out at the end of the day and can easily last more than three to six days. See our climate page for Greek weather statistics.
The surface flow is generally divergent in an Etesian situation, and the weather is generally thought to be dry with clear skies. However, this is mostly true only during July and August when scattered altocumulus appear a day before an Etesian, and the only other clouds are orographic types that may form on the lee side of islands in stronger Etesian winds.
The Meltemi occurs mainly during the summer season (June - September with 70%), but also in May and October one may frequently experience this dry wind. One should anticipate its maximum during July and August.
Due to the katabatic nature of the meltemi one can experience strong fall winds on the leeward side of the islands, notorious are Kea (we did survive though), Euboa, Tinos and Andros, Pholegandros, Kos, Serifos, Amorgos and Sifnos. An orographic cloud to leeward of the mountain spells danger.
When the wind encounters very high cliffs on the North shore of an island, a calm -extending several miles off shore- can be expected. Good examples are Amorgos, Paros and Naxos.
In the wide corridor between de dodecaneses and cycladen the Meltemi blows undisturbed over 100 miles. Within six hours of a 30 knot wind, the waves can reach heights over three meters. The adverse currents make these waves steeper, which can be seriously dangerous for yachts smaller than 10 meter.
Expect funnelling winds, which can make certain straits dangerous to pass because of currents and higher wind velocities. Classical areas are: between Andros and Euboa (currents up to 6 knots!); between Ikaria and Samos till the Phournoi-archipelago; Between Paros and Naxos; North side of Amorgos; West side of Karpathos. Sometimes South of both Kea and Kithnos.
Tell-tales for your own Meltemi 24-36 hour prediction:
A little history
Nowadays any soft and gentle breeze is referred to as a zephyr. Theophrastus, a 4th-century BCE scholar who left us with a complete accounting of the winds of Greece wrote: "Zephyros, the west wind, is the most gentle of all the winds and it blows in the afternoon and towards the land, and is cold,"...