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What exactly is the dew point? Why does it go up or down with temperature?
Thanks, Tee Jay P.
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The dewpoint, one of the most infamous terms in weather that confuses people and is commonly misunderstood.
The dewpoint simply put is the temperature the air would have to be cooled for saturation to occur. When the air is saturated we can see condensation or dew. The dewpoint also assumes there is no change in air pressure and moisture content in the air. We use the dewpoint to measure the humidity.
Dewpoint actually measures how much water vapor is in the air. The warmer it gets, the more water vapor the air can "hold". The higher the dewpoints, the higher moisture content of the air at that given temperature.
Dewpoints change depending on the moisture content of the air. You can have a 90 degree day with a 30 degree dewpoint or a 90 degree day with a 40 degree dewpoint.
The temperature cannot go above its dewpoint. Some links on the right will take you to some other pages which discuss this. At about a dewpoint of 60 F it starts to get uncomfortable, at 75 it's oppressive and at about 80, your body doesn't cool you with evaporating sweat anymore and it becomes dangerous to be exerting yourself outside.
Answered by KSL Meteorologist Dina Freedman
