Camera : Canon EOS 550D -- 6.15am
Wikipedia says mist is a phenomenon caused by small droplets of water suspended in air. Physically, it is an example of a dispersion. It is most commonly seen where warm, moist air meets sudden cooling. It can also occur as part of natural weather, when humid air cools rapidly, for example when the air comes into contact with surfaces that are much cooler than the air.
The only difference between mist and fog is visibility. The phenomenon is called fog if the visibility is one kilometre (1,100 yards) or less. Yesterday morning the visibility was about 50m, so technically I suppose this is fog!