Mist or Fog
The “calmest” form of special weather, mist or fog is nevertheless not to be taken lightly, It will occur beginning wither at sunrise (1-4 on 1D6) or at sunset (4-6 on 1D6) and will last for a number of hours equal to the result of the die roll. Fog will be heavy whenever it occurs in a seacoast area or in an inland location adjacent to a body of water. In all other locations it will be of moderate intensity. If precipitation occurs on the same day, the rain or snow will not fall while the fog condition persists, but it is 50% likely that a period of precipitation will immediately follow or preceded the fog (the former case for daytime fog, latter for nighttime.) See Effects of Reduced Visibility on Movement.