A wind rose is a graphic tool used by meteorologists to give a succinct view of how wind speed and direction are typically distributed at a particular location.
The length of each "spoke" around the circle is related to the frequency that the wind blows from a particular direction per unit time. Each concentric circle represents a different frequency, emanating from zero at the center to increasing frequencies at the outer circles.
Compiling a wind rose is one of the preliminary steps taken in constructing airport runways, as aircraft can have a lower ground speed at both landing and takeoff when pointing into the wind.