The meteorological wind direction is the direction from which the wind is blowing.
Wind direction increases clockwise such that a northerly wind is 0°, an easterly wind is 90°, a southerly wind is 180°, and a westerly wind is 270°.
Because trigonometry uses a polar coordinate system in which 0° is along the x axis, the meteorological angle definition can wreak havoc on typical angle calculations.
Fortunately, it is still easy to compute the wind components, u and v, given the meteorological wind angle. Let Φ be the meteorological wind direction angle, then the following equations can be applied:
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