What type of humidity measurement is primarily used in weather forecasting?

Relative humidity is the type of humidity measurement primarily used in weather forecasting because it provides a percentage of moisture in the air relative to the maximum amount of moisture that the air can hold at a given temperature. This measurement is critical in predicting weather conditions, such as the likelihood of precipitation, the formation of clouds, and overall weather patterns.

Relative humidity plays a key role in understanding how comfortable the air feels to people, as well as influencing processes like evaporation and condensation. When relative humidity is high, air can feel muggy, and the chances of rain increases. Conversely, when it is low, it can lead to dry conditions.

While other measurements like absolute humidity, dew point, and specific humidity are also important in meteorology, they do not convey the immediate, practical context that relative humidity provides regarding current conditions and subsequent weather forecasting.