Vector Wind Climatology: averages, of the same month, over a number of years, of wind speed at the earth's surface.
Click on the map to select the month you want. After you click the map, you will enter a month at the top of the figure where it says "Time:". Pick Jan,Feb,Mar,Apr,May,Jun,Aug,Sep,Nov,Dec. If you type the month wrong, you will get an error. Right click (or Control-Click for single button mouse's) to copy the image to your computer.