Dew Point
Dew Point
Dew point is the temp to which air must be at to reach saturation. At dew point or lower, water vapor begins to condense to a liquid or change to a solid (deposition). Dew point depends on the amount of water vapor present in the air.
Frost
Frost forms when air reaches the dew point temp, when the happens there is a possibility for dew or frost to form. Frost forms when dew point is below 0 degrees C (or 32 degrees F).
For Example
If humidity is high, only a small temp drop is needed to reach dew point. If humidity is low. a large temp drop is needed to reach dew point.