CHARLOTTE, NC (WBTV) - This time of year with high humidity always in the discussion along with the daily pop up showers, I get asked about why it doesn't always rain when the humidity is 100%. Or conversely, why does it sometimes rain when the humidity is low?
In the big picture, the amount of moisture in the air and the chances of rain are connected, but that has more to do with the water cycle in the atmosphere.
When lots of moisture (humidity) is available, clouds are more likely to form which eventually can lead to rain.
But it can be misleading trying to draw a direct correlation between humidity and precipitation. Remember, humidity is measuring how much water vapor (gas) is in the air, not liquid water.
These two exist in their own little worlds, even though there is certainly a bridge connecting them.
But a raindrop (if it had a brain) wouldn't care if it was falling through air with 25% humidity, except for the fact it would evaporate pretty quickly, but not instantly, as it fell through the dry layer.
Raindrops form in clouds high above the ground and they do form from saturated (100% Relative Humidity) air.