Groenvlei Wind Stats

The graph describes how commonly and how strongly the wind blows from different directions over a normal September. The longest spokes point in the directions the wind most commonly blows from and the shade of blue implies the strength, with deep blue showing the strongest winds. It is based on 3360 NWW3 forecasts of wind since since 2006, at 3hr intervals, for the closest NWW3 model node to Groenvlei, located 56 km away (35 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 most common wind at Groenvlei blows from the SSW. If the rose diagram shows a close to circular outline, it means there is no strong bias in wind direction at Groenvlei. Converseley, dominant spokes show favoured directions, and the more dark blue, the stronger the wind. Spokes point in the direction the wind blows from. During a typical September, the model suggests that winds are light enough for the sea to be glassy (the lightest shade of blue) about 11% of the time (3 days each September) and blows offshore 36% of the time (11 days in an average September). Over an average September winds stronger than >40kph (25mph) are expected on 4 days at Groenvlei

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