Due to geographical diversity, Croatian regions differ among each other in climate as well - from moderately warm and rainy climate in the interior, through cold winter climate in the mountain regions, to warm Mediterranean climate in the coastal area and on the islands.
In the coastal regions, average January temperatures range from 5°C to 9°C. In August they vary from 22°C to 25°C average, with sea temperatures from 12°C in winter to 25°C in the summer. Spring and autumn (April, May and October) are usually pleasantly warm, with somewhat stronger winds, which is attractive to more experienced yachtsmen.
Different types of wind that appear on Adriatic bring different problems or ease, for both locals and sailors. Bora is cold, abrupt and dangerous wind, but it also brings clear weather and fresher air. This is why most people like it better than sirocco (jugo, SE wind) which brings “heavy” air and low air pressure that cause headaches, bad mood and similar problems, especially in Dalmatia.
This cold SE wind blows from the mainland towards the open sea and brings bright weather. It starts suddenly and blows in gusts, strongest of which are in the Velebit channel and Gulf of Trieste. In the summer Bora is not as strong and abrupt as it is in winter. It lasts for a few day (sometimes less than 24 hours), but in winter it can last for up to two weeks.
Bora can be very unpleasant for smaller boats. Her vehement temper is the most dangerous thing about it, particularly for less experienced yachtsmen. As it appears suddenly and blows in gusts, it is very difficult to foresee it, and in the coastal area she reaches the speed of 40-50 knots (even more in winter). If Bora catches you at sea, the best thing to do is try to find some shelter at the SW foothills of the islands (the higher the island, the better).
Warm SE wind, known as sirocco, is created in the cyclone area and brings clouds, rain and low air pressure from the Mediterranean and south parts of Adriatic. It develops gradually and it usually can be noticed two or three days in advance, so you can plan finding a safe shelter. Sirocco is also responsible for very high waves, especially in the channels, and the best thing to do is to find cover in the nearest marina. However, if it catches you at sea, you should hide at the NE side of the islands. In summer, sirocco appears as the local wind (particularly in the south Adriatic), but in winter it often reaches north Adriatic as well. There are also so called dry southern winds that don’t bring rain but can have strength of a storm.
NW wind – mistral (meastral) is a mild, local summer wind that blows from the sea and brings clear sky and ease from the summer sultriness. It appears in the morning, grows stronger in the afternoon and ceases in the evening, when wind burin takes its place.
NE wind – burin is a summer wind that blows from the mainland. It is a light summer breeze that eases the heat of summer nights.
SSW wind – tramontana is a mild wind that appears due to air pressure changes between cyclones. You can feel strong tramuntana at a clear day.
Pulenat blows from the west. It is a short lasting but strong wind, often connected with the summer storms.
Lebić is caused by cyclonal and anticyclonal movments in the north, it blows from the SW and it can last for as long as two days. Occasionally, its strength increases which causes higher vawes alond the SW coasts.
Levant blows from the east, and is creadted when the influences of Bora and Jugo intermix. It brings humidity and low air temperatures.
Sudden, unexpected summer storms are, next to Bora, the most dangerous, especially for smaller boats. These are thermal storms that come racing from the open sea; they don’t last long, but are very powerful. They mostly appear in summer, and their power increases as the autumn approaches. As soon as you notice even the slighthest indication of storm approaching, quickly find cover because you have very little time. It would be best if you could completely get out of its way. These storms have caught many boats off guard because, prior to their appearance, the sea is unusaually calm, there is no wind or thunderstorms… only a few minutes before it strikes, you feel a breeze. This is way it is extremely important to pay attention to weather changes and weather forecast, because you’ll find yourself in great danger if one of these storms catches you at the open sea.
Radio stations along the coast broadcast weather information and forecast several times a day, in Croatian and English. Radio Rijeka, UKW channel 24 at 5:35 a.m., 2:35 p.m. and 7:35 p.m. Radio Split, UKW channels 07, 21, 23 and 81 at 5:45 a.m., 12:45 p.m. and 7:45 p.m. Radio Dubrovnik, UKW channels 07 and 04 at 6:25 a.m., 1:20 p.m. and 9:20 p.m.
Weather information for the territory of Cratian waters in Croatian, English, Italian and German are broadcasted constantly, every 10 minutes. The information is updated at 7 a.m., 1 p.m. and 7 p.m. local times. They briefly inform you on current weather situation and air preassure and give short forecast for the next 24 hours.
VHF-chanel 73 for North Adriatic / west coast of Istria VHF-kanalu 69 for North Adriatic / east region VHF-kanalu 67 for Middle Adriatic / east region VHF-kanalu 73 for South Adriatic / east region
(source: Croatian Tourist Board)