What does relative humidity (RH) measure?

Relative humidity (RH) is a crucial measure in understanding atmospheric conditions, particularly in relation to weather phenomena such as wildfires. It specifically quantifies the moisture content in the air by comparing the amount of water vapor present to the maximum amount of water vapor that the air can hold at a given temperature, expressed as a percentage. This measurement is essential because it provides insight into how conducive the atmosphere is to processes like evaporation, transpiration, and condensation, all of which influence fire behavior and spread.

Humidity impacts the way vegetation and fuel dry out; lower relative humidity levels can lead to drier conditions, which increase the likelihood of ignition and fire spread. Therefore, understanding relative humidity is vital for effective wildfire mitigation and management strategies, as it helps predict fire risks and inform decision-making regarding prevention efforts.

The other options pertain to different aspects of environmental science. Soil moisture measures water content in soil, wind speed refers to air movement, and temperature indicates the warmth or coolness of the atmosphere, none of which directly relate to the concept of relative humidity.