How to calculate wind direction from uwind and vwind?
if uwind and vwind are -1.82 , -3.18 respectively
The base formula for the direction $\theta$ is
Where $atan2$ is the four quadrant inverse tangent. Note that if you used the normal inverse tangent your results will be all collapsed to the first quadrant (0° to 90°). Also note that depending on the platform the result can be in radians or degrees (most often in radians, some platforms have a function atan2d that return values in degrees).
If you get a negative value (which is the same direction but measured counterclockwise), you have to add 360° (or $2\pi$ radians).
This will give you the direction the wind is coming from. For the direction is going to, you have to add/substract 180° (or $\pi$ radians).
For the values you provide, the answer would be 210°.