100% Humidity Question: Why isn't the humidity always 100% when it's raining? The Answer: What could be more humid than water pouring through the air in the form of raindrops? What could be clammier than shoes that have puddles *inside* them? Wouldn't air that's so humid that it's precipitating have to be up around the 100% mark? Remember that unless you have your head in the clouds or you're on a plane and the air-conditioning nozzle is dripping on you, precipitation comes from way above you. The meeting of two air masses usually generates rain. Often it results when the air up in the sky--where you should look for the 100% humidity--is moist and warm and the air down below is cool and dry. Humidity is measured at ground level. The rain itself will raise the humidity on the ground, but not necessarily to 100%. I hope that explanation wasn't too dry.