How are cloudiness and precipitation interrelated?

Cloudiness and precipitation are directly related. Cloudiness is a collection of clouds.
Clouds consist of water vapor, which turns into a liquid (rains and showers), amorphous (snow) or solid (hail) state and falls to the surface in the form of precipitation. Water changes its structure under the influence of cold or warm winds. So there is no precipitation without cloud cover. If the cloud cover is high and stays in place, the moisture level rises in the air and fog forms.