What does Relative Humidity (RH) represent?

Relative Humidity (RH) represents how much moisture is present in the air compared to the maximum amount of moisture that the air can hold at a given temperature. It is expressed as a percentage, indicating the degree of saturation of the air. For example, a relative humidity of 60% means that the air is holding 60% of the maximum water vapor it can contain at that temperature.

Understanding RH is crucial in meteorology as it influences weather patterns and comfort levels. High relative humidity levels can indicate possible precipitation and cloud formation, while low RH levels often suggest dry conditions. This concept is distinct from absolute humidity, which measures the total mass of water vapor in a given volume of air, not taking temperature into account. Furthermore, while the temperature at which air becomes saturated is known as the dew point, this defines a specific condition rather than percent saturation. The difference between actual and potential evaporation relates to water loss from surfaces, which is a separate topic. Overall, recognizing RH as the percent of saturation in the air is fundamental to grasping atmospheric moisture dynamics.