Relative Humidity and Rain

Relative humidity is the ratio of the actual amount of water vapor to the amount that would saturate air at the same temperature, expressed as a percentage. At 100%, the air is saturated; this can promote condensation, fog, or cloud formation. But 100% relative humidity does not automatically mean rain: precipitation requires suitable atmospheric processes, including air lifting and droplet growth. Relative humidity is not simply an absolute amount of water, because it depends on temperature.