Precipitation takes place when water condensation becomes sufficient that water droplets are heavy enough to fall back to the surface of the Earth. Precipitation is a very common phenomena in the atmosphere of our Earth. This precipitation always comes from clouds. Yet most clouds do not form precipitation.
This is because the water droplets and ice crystals found in most clouds are too small, and thus not heavy enough to fall to the surface of the Earth. A raindrop large enough to have the weight needed to fall to Earth is millions of times larger than the individual water droplets found inside most clouds.