• The air around us holds moisture. The amount of moisture that air can hold varies with temperature and pressure. Generally increase the temperature and you can increase the amount of moisture that the air can hold before being saturated.. Dew Point temperature is the temperature at which air, saturated with moisture is cooled sufficiently so that the moisture condenses to form water droplets (sometimes seen on grass early in the morning)
  • Water vapor (gas) is present in the atmosphere in varying amounts over time and space, and is constantly changing phase (gas to liquid, liquid to solid, etc.). The dew point is the temperature that the air must be cooled to in order to achieve saturation and/or condensation, seen as fog or dew on the grass. Another way of saying it is the dewpoint is the temperature that the air must be cooled to in order for net condensation to equal or exceed net evaporation. As a side note, there is a tendency for people to say "the higher the air temperature is, the more water vapor the air can hold." This is not technically correct, though you are getting the correct answer for the wrong reason. "Air" has no more "holding capacity" for water vapor than water vapor has a "holding capacity" for nitrogen or oxygen. There is simply a complex mixture of gases in the atmosphere. The warmer the air is though, the warmer the water vapor in the air is, and the more energetic the water vapor molecules are, so they can more readily evaporate, hence the fact that warmer air generally contains higher levels of water vapor.

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