If the dew point number is within one or two degrees F you'll get fog. If the dew point is 40, and the temp is between 38-42 degrees F you'll likely have fog.
Ok. Now explain Accuweather's RealFeel temperature.
They had to change it because most people didn’t pay attention in 8th grade science class and don’t understand “temperature humidity index” nor “wind chill”.
If you take the time it takes, it takes less time. --Pat Parelli
American by birth; Alaskan by choice. --ironbender