wind rose

A diagram for a given location showing the relative frequency and the velocity of the wind from a selected compass direction.

A wind rose indicates how wind speed and directions are typically distributed at a particular location. Presented in a circular format, the wind rose shows the frequency of winds blowing from particular directions. The length of each “spoke” around the circle is related to the frequency of time that the wind blows from a particular direction. Each concentric circle represents a different frequency, emanating from zero at the center to increasing frequencies at the outer circles. The wind roses shown here contain additional information, in that each spoke is broken down into discrete frequency categories that show the percentage of time that winds blow from a particular direction and at certain speed ranges. All wind roses shown here use 16 cardinal directions, such as north (N), NNE, NE, etc. This rose shows that the winds at this particular location in April blow from the northwest much of the time. In fact, the 3 spokes around the northwest direction (WNW, W, and NNW) comprise 50% of all hourly wind directions.