Wind

Wind is the horizontal motion of the air, usually due to pressure differences. The difference between pressures creates a force that makes the air move from high-to-low pressure regions as it tries to equalize the pressure. Wind vanes measure the direction from which wind is blowing on a 360˚ compass by tens, while a spinning device measures wind speed, called an anemometer. Wind traveling at one mph is also moving at 0.4 m/s or 0.87 knots.

You can identify the general direction that low and high pressures are located at just by the wind!