wind rose

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A meteorological diagram depicting the distribution of wind direction and speed at a location over a period of time.

from The Century Dictionary.

• noun A table or diagram showing the relative frequency of winds blowing from the different points of the compass, or the relative amount of total wind-movement for each direction; also, a table or diagram showing the connection between the wind-direction and any other meteorological element: thus, a thermal wind-rose shows the average temperature prevailing with winds from different directions.
• noun See rose and Rœmeria.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun meteorology A diagram in which the speed and direction of the winds at a particular location are represented by lines of varying thickness and length superimposed on a compass rose.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun weather map showing the frequency and strength of winds from different directions