Wind Rose Resources
What is a Wind Rose?
A wind rose gives a succinct view of how wind speed and direction 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. Wind rose example
Wind rose for July, Des Moines, Iowa. Click to enlarge.
About the Dataset
The National Water and Climate Center provides a dataset of wind rose plot images in .gif format. The images are organized by state, by city within each state, and then by month. The wind roses are based on hourly data from NOAA's Solar and Meteorological Surface Observation Network (SAMSON) dataset. The period of record is 1961-1990.
The wind roses in this dataset 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 in the dataset use 16 cardinal directions: north (N), north-northeast (NNE), northeast (NE), etc.
The legend at the bottom of the wind rose gives additional information such as the unit (m/sec), the average wind speed for the month over all hours, the percentage of time that the winds are calm, and the years, months, and hours of data on which each rose was constructed. All hours of the day (24 readings per day) are used to construct the wind roses.
Note: Wind speeds shown in the plots are in meters per second. To convert meters per second into miles per hour, multiply by 2.237. For example, a 5 m/sec wind converts to a 11.19 mph wind, and a 10 m/sec wind converts to 22.37 mph. In addition, anemometer heights were not adjusted to a common height in the SAMSON dataset. For more information, a spreadsheet containing the anemometer height history in meters and feet at each station is available here.
More on the SAMSON dataset
WRPLOT View™ Wind Rose Plots for Meteorological Data. Free software download.
Iowa Environmental Mesonet Wind Rose Plots. Select State and Station to display plots.