Birsay Bay Wind Stats

The figure illustrates how often and how strongly the wind blows from different directions through a typical April. The biggest spokes point in the directions the wind most commonly blows from and the shade of blue indicates the strength, with deep blue showing the strongest winds. It is based on 3360 NWW3 forecasts of wind since since 2007, at 3hr intervals, for the closest NWW3 model node to Birsay Bay, located 17 km away (11 miles). There are not enough recording stations world wide to use actual wind data. Invevitably some coastal places have very localized wind effects that would not be predicted by NWW3. According to the model, the prevailing wind at Birsay Bay blows from the WNW. If the rose plot shows a nearly round shape, it means there is no strong bias in wind direction at Birsay Bay. On the other hand, dominant spokes show favoured directions, and the more deep blue, the stronger the wind. Spokes point in the direction the wind blows from. Over an average April, the model suggests that winds are light enough for the sea to be glassy (light blue) about 4% of the time (1 days each April) and blows offshore just 32% of the time (10 days in an average April). In a typical April winds stronger than >40kph (25mph) are expected on 4 days at Birsay Bay

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