What is relative humidity?

Relative humidity is defined as the amount of moisture in the air compared to the maximum amount of moisture that the air can hold at a given temperature, typically expressed as a percentage. This measurement provides important context for understanding atmospheric conditions, particularly for aviation and meteorology.

When relative humidity is at 100%, it means the air is fully saturated with moisture, and any further cooling or addition of moisture can lead to condensation, such as fog or clouds. A lower relative humidity percentage indicates that the air is capable of holding more moisture, which can affect weather patterns and visibility conditions relevant to drone operations.

Understanding relative humidity is crucial for unmanned aircraft operators, as changes in humidity levels can impact flight performance, stability, and safety. For instance, flying in conditions with high relative humidity may affect the drone's sensors or battery performance.

The other choices provided do not accurately define relative humidity. The absolute amount of moisture in an air mass focuses solely on the quantity of water vapor without considering temperature, while the temperature at which air cannot hold moisture and the difference between the temperature and dew point refer to different aspects of atmospheric science that do not encompass the concept of relative humidity.