What is the dewpoint?

March 31, 2008 1:54:49 PM PDT
The dewpoint is the temperature at which fog forms.

Erica's Answer:

So, if the air temperature is 40 degrees and the dewpoint is 40 degrees, fog would be present. We could just as easily call the dewpoint the "fog point", because dew and fog form due to the same process! Dew forms when air cools down to its dewpoint, which is the same way fog forms.

- Erica