Dewpoint
The dewpoint is the temperature at which air must be cooled to become saturated with water vapor.
Temperature / Dewpoint Spread
The difference between the ambient temperature and the dewpoint determines the relative humidity of the air, and whether clouds and fog are likely to form.
- When the temperature and the dewpoint are the same, relatively humidity is 100%
- When the temperature is withim 5° C of the dewpoint, clouds, dew, and fog
are likely
- This is also the most favorable conditions for carburetor icing