DEW
If the temperature of the ground falls below the dew point of the air, the air deposits on the cooler surface moisture in the form of small drops of water, which we call dew drops. Where the temperature of the ground becomes cooler than the air above it, a rapid cooling by radiation on a clear night has taken place; and if the dew point or frost point has been reached by the ground, the air just above the point is several degrees warmer.