Here's why:

* Clouds are formed by condensation: Warm, moist air rises and cools. As it cools, the water vapor in the air condenses into tiny water droplets or ice crystals, forming clouds.

* Clouds provide a source of moisture: These water droplets or ice crystals within clouds are the very source of precipitation.

* Precipitation forms within clouds: As water droplets collide and grow larger, or ice crystals fall and melt, they become heavy enough to fall to the ground as rain, snow, sleet, or hail.

So, while clear skies can be beautiful, they lack the necessary ingredient for precipitation—the moisture-laden clouds!