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

Humidity levels remain the same with dew points in the mid-70s or so.

From Washington Post

We may have dew points heading back down into the comfortable 50s.

From Washington Post

The dew point of 49 degrees that was recorded in the middle of the day is something we might expect about 1 percent of the time.

From Washington Post

Humidity remains fairly high with dew points in the upper 60s to near 70.

From Washington Post

When combining Tuesday’s air temperature and dew point, our skin can’t self-cool as easily, so the apparent “heat index” temperature may feel about 100 degrees in a few locations.

From Washington Post

Hence the utility of instruments for determining the dew-point.

From Project Gutenberg

The temperature at which air is saturated and condensation begins is called the dew point.

From Project Gutenberg

As soon as a mass of air is cooled to its dew-point, water begins to be precipitated in the form of rain, dew, snow or hail.

From Project Gutenberg

This temperature is the dew point of the air after it passes up into the drying chamber above the coils.

From Project Gutenberg

Knowing the temperature in the drying room and the dew point, the relative humidity is thus determined.

From Project Gutenberg