I am a writer. In my fictional world, I have an area that is supposedly covered with fairly thick fog during most of the night and nearly all of the morning, basically every day (it can leave a bit before noon if necessary). My question is this: What factors would I need to achieve this effect?
Factors: It is a fantasy world, so the factors need to be natural. The area is within a city, and is very densely inhabited. The area is enclosed by large trees, and large roots run all over the ground. The fog does not need to reach any higher than 7 feet, but it does need to cover nearly the whole area (a generous approximation would be 288 ft by 228 ft - about 65,000 square feet). The walls of the area (giant roots/tree trunks) vary in distance from each other a lot.
Topography: There is a massive forest a few hundred yards away from the city on three sides. On one side stretches a generally flat plain. The city itself is on a fairly flat piece of land. Rain water is collected and can be found in large standing pools throughout the city (don't think fountains. Think small swimming pools.). I can somewhat alter the topography if needed.
Let me know if you need more details on the surroundings.