Every time I read about it it trails into complex physics
In: 6
Example:
Today it’s 64 F and humidity is 78%
Dew point is 45F (I completely made this number up for the example)
If you cool the air you have at this moment, down to 45F, you get fog/dew.
The reason is hot air can host more humidity than cold air. If the hair is full of water and it cools, the water will be expelled by the air. And you get wet even if it’s not raining. Dew point is a quick reference for the complex calculation. Someone does the math for you, and just tell you how far colder you need to get today before you get dew.
Most importantly, when you are below icing temperature, getting to dew point means you get sudden ice over things, as water is expended by air, below the freezing point. So ice is suddenly “coming out of the air”. For example, plane wings, wind turbines, power cables, even roads in a very windy day can get a dangerous ice layer quickly from passing the dew point. The more air movement there is (bind or vehicle movement) the quicker it builds up.
It’s a good reference to know how far, therefore how likely, you are gonna be affected by dew, fog, or icing.
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