dew point

noun

1. 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.

dew point

noun

1. the temperature at which water vapour in the air becomes saturated and water droplets begin to form

dew point

1. 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.

Word History and Origins

Origin of dew point¹

First recorded in 1825–35

Example Sentences

Firstly, there’s the cooling and condensation process which cools humid air to its dew point, causing water vapour to condense into liquid water.

From BBC

According to AccuWeather’s chief meteorologist Jonathan Porter, their index factors in weather conditions that NWS’s wind chill does not, such as dew point, cloud cover, and precipitation.

From National Geographic

Cooled by the ground, the dropping air temperature can approach the dew point, and if there is sufficient moisture in the air, fog begins to form, becoming the most dense around sunrise when surface temperatures are lowest.

From Science Daily

Two lines tracking dew point and temperature converged.

From Los Angeles Times

And since air temperatures cool with height, that air parcel may be chilled down to its dew point as it ascends.

From Washington Post