How does altitude affect the value of dew point?

The relationship between altitude and dew point is fundamental to understanding atmospheric processes. As altitude increases, temperature generally decreases. The dew point is the temperature at which air becomes saturated with moisture and begins to condense into dew.

In practice, for every 1,000 feet gained in altitude, the temperature typically decreases by about 2 degrees Celsius (a standard lapse rate). The dew point will follow a similar trend, meaning that as altitude increases, the dew point also decreases, but not by a set formula of half a degree.

The chosen answer suggests a specific decrease in dew point with altitude, which reflects how the saturation point lowers as the temperature drops due to altitude gain. This reduction is more nuanced than simply "reducing the dew point by half a degree" since it is directly related to the relative humidity of the air at that height. In reality, the dew point does not follow a strict linear reduction but often correlates with humidity levels and environmental conditions.

Understanding this relationship helps explain why weather patterns and cloud formation can vary significantly with changes in altitude. The correct conception is that as you ascend into the atmosphere, the conditions that affect moisture levels and saturation shift, leading to a decrease in the dew point as the temperature cools further.