At what rate will dewpoint drop as pressure decreases?

The dew point tends to decrease with decreasing pressure in the atmosphere. This relationship is important for understanding how moisture behaves as altitude changes. Specifically, the dew point typically drops at a rate of approximately 0.5 degrees Celsius for every 1,000 feet of altitude increase.

This drop in dew point with altitude is primarily due to the fact that as you ascend, the pressure decreases, leading to lower temperatures and reduced capacity for the air to hold moisture. The 0.5-degree rate reflects a typical average in stable atmospheric conditions, where there is a consistent drop in temperature and moisture characteristics with an increase in elevation. Understanding this rate is essential for pilots and meteorologists when predicting weather and assessing flight conditions, especially related to humidity, cloud formation, and potential turbulence.