Why is moisture necessary for precipitation to develop?

The moisture is important for precipitation to develop because it is consisted of water vapor.

The moisture is consisted of water vapor. The water vapor is less dense than the air and it moves upwards. When it reaches certain height where the temperatures drop to a point where the water vapor transforms from gas to liquid, the process of condensation, clouds start to form. The clouds when saturated enough with microscopic drops of water start to produce rain, thus precipitation. 

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