dew point
Definition
- Noun:
- The temperature at which air becomes saturated with water vapor, causing dew to form: The dew point is the specific temperature to which air must be cooled at constant pressure for water vapor to begin condensing into liquid water (dew, fog, or cloud droplets). It is a direct measure of the amount of moisture in the air.
Usage
- The dew point is a crucial concept in meteorology, aviation, and HVAC (heating, ventilation, and air conditioning).
- It is used to describe humidity more accurately than relative humidity alone. A higher dew point indicates more moisture in the air.
- It is typically used in sentences like: "The dew point is..." or "When the temperature drops to the dew point..."
Examples
- Noun:
- The dew point tonight is forecast to be 15°C, so you might see fog in the morning.
- When the air temperature and the dew point are the same, the relative humidity is 100%.
- A dew point above 21°C (70°F) is generally considered uncomfortable and humid.
Advanced Usage
"Dew point depression": The difference between the air temperature and the dew point temperature. A smaller depression indicates higher humidity.
- With a dew point depression of only 2 degrees, the air feels very muggy.
"Frost point": A related concept; the temperature at which water vapor sublimates directly into frost. This occurs when the dew point is below freezing.
Variants and Related Words
- Dew (n): Tiny drops of water that form on cool surfaces at night when atmospheric vapor condenses.
- The grass was covered in dew.
- Condensation (n): The process of a gas changing into a liquid, which occurs at the dew point.
- Condensation formed on the cold glass.
Synonyms
- Saturation temperature (in the specific context of atmospheric water vapor).
- Condensation point.
Related Phrases
- To reach the dew point: Describes the moment when cooling air becomes saturated.
- The air will reach its dew point just before dawn.
- Dew point temperature: A more formal, explicit term for .
- The meteorologist calculated the dew point temperature.
Noun
-
the temperature at which the water vapor in the air becomes saturated and condensation begins
