The Adriatic is generally regarded as an area with light winds. In summer, it is mostly a dead calm along the eastern coastline at night and early morning, or only a light breeze blows. During the day, winds especially pleasant for yachtsmen blow from the northwest. Less suitable yachting conditions can be found around the eastern coastline of Istria, along the coastline between Rijeka and the Novigrad Sea, and between Split and Ulcinj.
The Mistral (a day breeze)—A fair weather wind
A southwesterly to northwesterly wind known as the Mistral (sometimes called the Maestral or Maestro) predominates in the Adriatic from the start of June to mid-September. This wind is caused by day thermals, which are columns of rising air caused by the uneven heating of the mainland and the sea.
It usually starts blowing around 10:00 in the morning and can reach a strength of 3 to 5 on the Beaufort scale (BFT) in the afternoon. At sunset it stops again. The Mistral is considered a fair weather wind because it accompanies a cloudless, blue sky and pleasant temperatures at sea. If it does not persist the next day, this could be a sign that the weather is worsening. In recent years, the Mistral has blown somewhat less frequently than previously. But it still does occur, particularly in the area around the outer islands.
Sirocco—Bad weather wind
The Sirocco blows from southerly directions, mainly from the southeast, and is only different than the Mistral in wind direction. The weather it brings to the Adriatic is accompanied by sultriness, overcast skies, and frequent showers. Sometimes, especially in winter, the Sirocco reaches gale force. Between mid-June and mid-September, the Sirocco rarely appears. In summer, it lasts for 2–3 days and almost never reaches a strength of more than 7 BFT.
However, from October to May, this wind blows significantly more often, longer, and with greater force, up to 9 BFT. Because the Sirocco blows a long distance over the sea, it creates large waves 3-4 m high, especially in the northern Adriatic. There are dangerous places near the northern Italian coastline where waves can reach all the way down to the bottom of the sea. But the Sirocco is preceded by clear signs, so it is possible to prepare for it in time.
Bora—Attaining gale force
The Bora is a "speciality" of the eastern coastline of the Adriatic and is a dangerous wind in this area. Mainly when there is high pressure and the sky is very clear, gusts of stormy winds start to blow from what is literally a blue sky from the northeast, descending to the surface and swelling up in blankets of foam across the sea and islands. The occurrence of the Bora is mainly caused by the Dinaric Alps which run parallel to the eastern coastline of the Adriatic. These mountains are not fully interrupted by any deep lateral valley through which the cold wind between the mountains could flow to the sea. Another condition for the creation of a Bora is the difference in air pressure between the inland and the Adriatic. The greater the difference in pressure, the more likely and more dangerous the Bora will be.