Dew is a meteorological phenomenon that results in the condensation (liquefaction) of the humidity in the air onto surfaces of the ground, plants and objects.
Dew forms during the evening or in the morning, when the temperature of the said surfaces drops until it reaches the dew point, and when the ambient air humidity is sufficient. Water vapour then condenses on the cold surfaces.
Use of dew
This phenomenon is used by some plants and animals in environments where fresh water is very rare. Some devices, such as cloud wisps, are also used to produce drinkable fresh water from dew.
Drops of dew on blades of grass. © Simon Allard CC by-nc-sa 2.0