- the temperature to which air must be cooled, at a given pressure and water-vapor content, for it to reach saturation; the temperature at which dew begins to form.
Origin of dew point
First recorded in 1825–35
Also called dew-point temperature.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for dew point
The temperature at which the haze first appears is the dew-point.
The temperature on this horizontal line at the point reached will be the dew-point.
This is dew; and the temperature at which the air is saturated with vapor, is called the dew-point.Farm drainage
Henry Flagg French
Amongst the various contrivances for accomplishing859 this end are Daniels dew-point hygrometer; and the wet bulb hygrometer.
Hence the utility of instruments for determining the dew-point.A Treatise on Meteorological Instruments
- the temperature at which water vapour in the air becomes saturated and water droplets begin to form
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- The temperature at which the water vapor contained in a volume of air at a given atmospheric pressure reaches saturation and condenses to form dew. The dew point varies depending on how much water vapor the air contains, with humid air having a higher dew point than dry air. When large droplets of condensation form, they are deposited onto surfaces as dew. When smaller droplets form, they remain suspended in the air as mist or fog. If the dew point is below the freezing temperature of water (0°C), the water vapor turns directly into frost by sublimation.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.