Description:

Visibility is measured using a visibility meter or visibility sensor.

A visibility meter (also called a transmissometer or forward scatter visibility sensor) measures the clarity of the atmosphere by determining how much light is scattered or absorbed by particles like fog, dust, or smoke. It is commonly used at airports and weather stations.

• Barometer: Measures atmospheric pressure.
• Hygrometer: Measures humidity (moisture content in the air).

So, the correct answer for measuring visibility is a visibility meter or visibility sensor.