As air gets colder, it can't hold as much moisture. So if the air cools enough, the humidity will reach 100% capacity and the water will be forced to condense.
As water vapor cools to the dew point it converts from a gas back to a liquid.
When air is cooled to its dew point, it reaches a temperature at which its water vapor condenses into liquid water. This forms tiny water droplets which ultimately become visible as fog, mist, or dew on surfaces. Dew point is the temperature at which the air becomes saturated with water vapor and cannot hold any more, leading to the condensation of excess vapor.
Dew point is the temperature at which air becomes saturated with water vapor, causing condensation to form dew. It is a measure of humidity in the air, with higher dew point values indicating more moisture in the atmosphere. Dew point is often used in weather reports to describe how muggy or dry the air feels.
condensation Another question that follows: As an air mass cools to its dew point; relative humidity increases
Condensation
If the temperature of the ground, grass, and other surfaces is warmer than the dew point of the air that comes in contact with the surfaces, dew will not form. Sometimes this happens when the air is really dry and the dew point is very low.
supercooled
it grows testicles
Condensation occurs when air reaches its dew point, which is the temperature at which air becomes saturated with moisture and can no longer hold it in gaseous form. When air cools to its dew point, water vapor in the air condenses into liquid water, forming dew or fog.
dew point
the realationship between condensation and dew point is that condensation occurs when it reaches the dew point.
The Dew Point is the temperature at which the air is at 100% Relative Humidity. If the temperature fall below the Dew Point, then there is more moisture in the air than it can hold, and water condenses in the form of dew, mist, rain, etc.