Which of the following best describes an anemometer?

An anemometer is specifically designed to measure wind speed. It typically consists of rotating cups or blades that catch the wind, with the speed of rotation correlating to the wind speed. This makes it an essential tool in weather observation, as understanding wind speed is crucial for various meteorological analyses and forecasts. By providing accurate measurements, an anemometer helps meteorologists and weather observers assess conditions that can impact weather patterns, such as storm development and movement.

In contrast, the other options refer to different instruments: devices for measuring atmospheric pressure (barometers), tools for measuring temperature (thermometers), and types of charts that represent cloud formations (cloud charts), none of which pertain to wind speed measurement.