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:
Note that Φ must be in radians. If Φ is in degrees, multiply the angle by π/180 before using the trig function.
It is also possible to compute Φ from u and v using the atan2 function. The atan2 arguments vary by type of software.
On a spreadsheet, use the following equation to get an answer in degrees:
Note, in many applications the arguments v, u are switched around.
