Not sure you're correct there TartanWizard. Fog is defined as "Condensed water vapor in cloudlike masses lying close to the ground and limiting visibility" While mist: "A mass of fine droplets of water in the atmosphere near or in contact with the earth" I seem to remember from GCSE geography that the meteorological distinction is in the amount it limits visability, I might go and have a look on the met office website see if the know

Hmmm... This is actually a disputed area. The one I was taught during my geography degree is one of visibility. If it you can see less than 1000 yards, then it's fog. If it's more, then it's mist. However, I've also seen claims for droplet size and Tartanwizard's answer above!

I checked with the Met Office site and your memory is correct Waldo! If the water droplets reduce visibily below 1000m (not yards - probably changed to metric over the years!) then it is fog.

They are both probably right to some degree. :) When you think about it, water vapour that is 'mist' which technically lies 'near to the surface of the earth', then it will likley not restrict your vision by more than 1 km, where as, 'fog', which (rises from and) lies on the ground, will almost certainly restrict vision more than mist will. Of course, under extreme conditions, or in mountainous areas, the 'distance' rule is probably better to help describe the situation, where clouds would form mist on the 'ground', even though that ground was much higher than then valley below it.