Meteorological instruments are used to measure various atmospheric conditions. Key instruments include thermometers for temperature (degrees Celsius/Fahrenheit), barometers for pressure (hPa, mb), anemometers for wind speed (m/s, km/h), rain gauges for precipitation (mm), and hygrometers for humidity (percent relative humidity). Other instruments such as ceilometers, disdrometers, and weather balloons equipped with radiosondes are used to observe clouds, raindrops, and wind/temperature/pressure profiles at different altitudes. Measurements from these instruments provide critical data for weather forecasts and climate studies.