The primary method of measuring relative humidity is using a hygrometer. Hygrometers can be mechanical, electronic, or chemical devices that assess the moisture content of the air. One common type of hygrometer is the psychrometer, which uses two thermometers—one wet and one dry—to determine humidity levels based on the difference in evaporation rates. Precise measurement of relative humidity is vital for various applications, including weather forecasting, climate studies, and managing indoor air quality. Understanding humidity also helps in agriculture and controlling environments for optimal growth conditions.