What is Pressure Dew Point?

The Pressure Dew Point (PDP) is a measure of how dry or moisture-free the air is at a given pressure. It tells us the temperature at which water vapor in the air will begin to condense into liquid water when the pressure is constant. The PDP scale is typically measured in degrees Celsius (°C). The lower the PDP temperature, the drier the air. Heres a simplified explanation of the PDP scale: Lets say we have a PDP of -20°C. This means that when the air temperature drops to -20°C, water vapor in the air will start to condense and turn into liquid water. In other words, the air is relatively dry because it can tolerate colder temperatures before water droplets form. On the other hand, if we have a PDP of 0°C, it means that the air is not as dry. Once the temperature drops to 0°C, water vapor in the air will start to condense and form liquid water. This indicates that the air contains more moisture and is less capable of tolerating colder temperatures before condensation occurs. In summary, the Pressure Dew Point scale in degrees Celsius tells us the temperature at which water vapor in the air will begin to condense into liquid water when the pressure remains constant. The lower the PDP temperature, the drier the air, and the higher the temperature, the more moisture it contains.