Windrose

Soure: http://commons.wikimedia.org/wiki/file:windrose.svg

Direct link to image: http://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/Windrose.svg/600px-Windrose.svg.png

A wind rose can either be a map symbol showing, for a given locality or area, the frequency and strength of the wind from various directions, or a diagram showing the relation of wind direction to other weather conditions at a given location.