Air is always saturated. You probably haven’t noticed because the air around you is constantly changing as it goes from being colder to warmer, and back again. This means that even when the air seems dry and desert-like, there are still some water vapor molecules suspended in it waiting for a chance to condense into droplets of water or ice particles. You probably haven’t noticed because the air around you is constantly changing as it goes from being colder to warmer, and back again. This means that even when the air seems dry and desert-like, there are still some water vapor molecules suspended in it waiting for a chance to condense into droplets of water or ice particles. The air’s saturation is measured by a humidity gauge, and it ranges from 0 to 100%. In the desert on a dry day when there isn’t much water vapor in the air, ground level relative humidity may be as low as 20%, but at night after lots of people have been breathing out moist indoor air while windows are closed for hours or overnight the relative humidity can rise up into the 60% range. A very humid atmosphere might have an 80-90% relative humidity reading. Humidity gauges measure how many liquid droplets (or ice) particles will form per cubic meter of air that rises one meter off the surface where it was created before falling back down again. But because this measurement doesn’t include invisible water
