Winter

• Easterly to northeasterly winds predominate during the winter season, reflecting a high frequency of bora events along the Croatian coast. January has the highest annual relative frequency of severe bora winds (mean hourly wind speed > 34 kt; 17.5 ms -¹) and the highest relative frequency of number of hours with the severe bora. However, these effects are experienced only weakly at Zadar, due to the flat topography in the area and the fact that mountains, instrumental in producing such effects, are some distance away.

• The jugo or scirocco and lebic also have a high frequency during the winter season, and these do raise high seas at anchorage locations in Zadarski Kanal. The winds of a "severe" jugo having speeds of greater than 34 kt (17.5 ms-¹) last only about 5 hours, but on exception, can extend to 25 hours. Strong jugos with winds from 21 -34 kt (10.8 - 17.5 ms-¹) have an average duration of 19 hours, and with exception to 36 hours. The highest mean hourly wind speed for a jugo in the Adriatic, based on data from 1958-1987, was 53 kt (27.3 ms-¹). This occurred on 21 March 1971.

• Despite the above information concerning high winds, it is important to realize that there are winter periods when high pressure dominates the region, and seas can be essentially calm for periods of several weeks.

• It is also a statistical fact that the dominant wind speed in the region during winter is <10 kt (5 ms-¹) and that the tendency for higher average wind speeds is during the spring.