Which instrument is used to measure wind speed?

The instrument specifically designed to measure wind speed is the anemometer. Anemometers work by using various mechanisms, often involving rotating cups or blades that rotate more or less quickly in response to wind velocity. The speed of this rotation is then translated into a measurement of wind speed, typically expressed in miles per hour or meters per second.

In contrast, a barometer is primarily used to measure atmospheric pressure, which can indicate changes in weather but does not provide information about wind speed. A thermometer is designed to measure temperature, and while it is essential for understanding weather conditions, it does not relate directly to wind speed. A hydrometer measures the specific gravity or density of liquids, particularly used in fields like brewing or chemistry, and is unrelated to atmospheric wind conditions.