This message explains "how clouds affect humidity", posted 3/1/2000 by Cloud
                 Masters. Hope this helps! - C. Duvall, Rutgers Univ. Meteorologist 

                 A. Relative Humidity and Precipitation: 

                 Please scroll down the message list to see the messages titled: 

                 " **Relative Humidity** " 
                 " **Precipitation and Hail** " 

                 to learn the basic idea behind humidity and the formation of clouds and rain. If you
                 cannot find these messages, a partial summary is provided below. However, I
                 would suggest that you read these messages to really understand this topic. 

                 B. Clouds affecting humidity: 

                 Clouds are bubbles of air which have been cooled so the air temperature is equal to
                 the dewpoint temperature, or the bubbles of air have 100% relative humidity. When
                 this point is reached, the invisible water vapor in the air "condenses", or forms
                 visible cloud droplets. Roughly one MILLION cloud droplets need to combine with
                 each other to form ONE raindrop! 

                 So clouds do not really affect humidity, they are a visible result of reaching a
                 certain level of relative humidity (100%). Clouds at ground level are called fog.
                 Dew and frost can form when the air right next to grass, windows, and other things
                 at the surface reaches 100% relative humidity, too, so keep in mind that clouds are
                 not the only possibility. 

                 Hope this helps! 

                 - CD 3/1/2000