Wind direction is the compass point from which the wind is coming eg south, south west, west etc.
The unit of measurement for wind direction is therefore compass direction. We plot the wind direction for each day of the month on a special graph called a wind rose i.e. The number in the centre of the wind rose tells us how many days in the month were calm. The wind directions in the table below have been plotted on this wind rose graph. The direction from which the wind blows most frequently is called the prevailing wind . Plot the wind directions given in the table below onto Graph 3 on your worksheet.