Duggpunkt

Duggpunkt, also rendered as duggpunkt in several Scandinavian languages, is the temperature at which air becomes saturated with water vapor and condensation begins, producing dew on surfaces. It is a measure of atmospheric moisture and depends on the current air temperature and relative humidity. When the air cools to the dew point at a given pressure, the water vapor can no longer be held in vapor form and droplets form.

In meteorology, the dew point is reached when the air’s relative humidity is 100%. The smaller the gap between the air temperature and the dew point, the more humid the air feels. A dew point close to the air temperature indicates high moisture content, while a dew point well below the air temperature indicates dry air.

Calculation and estimation: The dew point can be estimated from measured temperature and relative humidity using formulas such as the Magnus–Teten approximation. A common form is gamma = (a*T)/(b+T), and Td = (b*gamma)/(a-gamma), where Td is the dew point, T is air temperature, and a and b are empirically derived constants (for example a = 17.27 and b = 237.7°C). Other equations and numerical methods are used in weather models and sensors.

Measurement and use: Dew point is measured directly with dedicated dew point hygrometers or inferred from temperature and humidity sensors. It is widely used in weather forecasting, HVAC design, agriculture, and building science to assess condensation risk, comfort, and fog formation. See also humidity, fog, and frost point.