On the global scale, areas nearer the equator receive more energy from the sun than the polar regions. This means that the equatorial regions are warm and have generally low pressure, while the colder regions have higher pressures. To balance these temperature differences, air flows from areas of high barometric pressure to low pressure. This movement of air we call wind. To measure winds, you have to consider the speed of the wind and its direction.
Wind speed is measured with an anemometer.
There are many types, but the most common consists of three small cups that catch the wind and spin. The faster they spin, the greater the wind speed. Wind direction is determined using a wind vane. Because of the variable nature of wind, the usual convention is to average wind speed and direction over two minutes. The winds that are felt many afternoons from late spring and into autumn result from the aforementioned temperature differential.