<p>The heat of the Sun can "burn off" fog. So a lack of direct sunshine, cool temperatures &amp; humidity (evaporation of water from a nearby body of water or saturated or wet ground) are key to maintaining fog. The air must be moist!</p>

CC BY-SA 3.0
2015-01-21T00:02:33.843Z
2015-01-21T00:02:33.843Z
Fred
<blockquote>
  <p>This question is now <a href="https://worldbuilding.stackexchange.com/questions/9013/how-can-i-keep-dense-fog-in-an-area-for-half-a-day">here</a> on Worldbuilding Stack Exchange </p>
</blockquote>

<p>I am a writer, and this question is for a fictional work. However, given its nature, I believe it is better suited here than Writers Stack Exchange. </p>

<p>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 (it can leave a bit before noon if necessary). My question is this: <strong>What factors would I need to achieve this effect?</strong> </p>

<p>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. </p>

<p>Let me know if you need more details on the surroundings. </p>

CC BY-SA 3.0
2015-01-20T20:48:05.270Z
I think to fully answer - it would be very interesting to know more about the local topography (valley, mountain, field, peninsula?) Also what about the presence of a water body (seashore, lake, river)? I am asking because those are some factors which may be important regarding the formation of a  fog, IMO.
marsisalie
CC BY-SA 3.0
2015-01-20T21:01:01.860Z
Off-topic. Belongs on http://worldbuilding.stackexchange.com.
milancurcic
CC BY-SA 3.0
2015-01-20T21:16:06.413Z
The easiest thing would be to put the city in an elevated area (e.g. on the side of a volcanic mountain) such that ground level is regularly exposed to clouds passing by.
f.thorpe
CC BY-SA 3.0
2015-01-20T21:33:45.843Z
Thank you, @milancurcic I will ask the question there, and put in the details mentioned in the other comments as well.
Tommy Myron
CC BY-SA 3.0
2015-01-20T22:01:12.970Z
@milancurcic Agreed: this is *exactly* the kind of question that the worldbuilding SE exists for. It took some discussion in meta.earthscience even to agree that (real, observable) non-Earth planets can be on-topic here -- imaginary worlds would definitely be a step too far! (But I can't resist mentioning in passing that, in a densely inhabited city, [smog](http://en.wikipedia.org/wiki/Great_Smog) would appear to fit the questioner's requirements rather neatly.)
Pont
CC BY-SA 3.0
2015-01-21T00:13:28.773Z
@Pont It would... except that it is a fantasy world, and so smog is not present. I didn't realize the World Building Beta existed when I asked this, which is why I put it here. Sorry about that.
Tommy Myron
CC BY-SA 3.0
2015-01-21T00:37:04.363Z
The question is now on [Worldbuilding](http://worldbuilding.stackexchange.com/questions/9013/how-can-i-keep-dense-fog-in-an-area-for-half-a-day).
HDE 226868
CC BY-SA 3.0
2015-01-21T02:05:59.903Z
Although the context for the question is a fictional world, it is still relevant to the natural world. The city could also be in a low-lying area where the valley 'fills' with fog and I believe that would be more conducive to regular persistent fog than on the side of a mountain. Conceivably could be subject to coastal fog like San Francisco.
haresfur
CC BY-SA 3.0
2015-01-21T08:46:47.900Z
@TommyMyron I wouldn't have thought "fantasy world" *per se* necessarily precludes smog (you can find smog in e.g. *The Lord of the Rings*). But of course in your own world you make the rules, and this kind of arbitrary constraint is exactly what pushes it out of Earth Science territory. But I see you're getting good answers already over on worldbuilding, so good luck finding something that fits the bill!
Pont
CC BY-SA 3.0
2015-01-21T15:36:41.703Z
@TommyMyron crossposting is discouraged.  In the future if you feel your question is better suited for a different stackexchange site, you can flag your question for migration to that site.
casey
CC BY-SA 3.0
2015-01-22T03:13:07.233Z
@TommyMyron: You could edit this question to be on-topic on this site, and keep the WorldBuilding.SE question as is. Something along the lines of *"Are there any parts of the world that regularly have fog until late morning, and if so, what factors cause that phenomenon?"* or just *"What causes late-morning fogs?"* would be pretty on-topic, and would complement this question on WB.SE.
naught101
<clouds><hypothetical><humidity>
Fictional Land - How can I keep dense fog in an area for half a day?
Tommy Myron
# Fictional Land - How can I keep dense fog in an area for half a day?

(Asked by: username_0 on 2015-01-20)

> This question is now [here](https://worldbuilding.stackexchange.com/questions/9013/how-can-i-keep-dense-fog-in-an-area-for-half-a-day) on Worldbuilding Stack Exchange

I am a writer, and this question is for a fictional work. However, given its nature, I believe it is better suited here than Writers Stack Exchange.

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 (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.

Let me know if you need more details on the surroundings.

**Tags:** clouds, hypothetical, humidity

> **Comments:**
> **username_1**: I think to fully answer - it would be very interesting to know more about the local topography (valley, mountain, field, peninsula?) Also what about the presence of a water body (seashore, lake, river)? I am asking because those are some factors which may be important regarding the formation of a  fog, IMO.  
> **username_2**: Off-topic. Belongs on http://worldbuilding.stackexchange.com.  
> **username_3**: The easiest thing would be to put the city in an elevated area (e.g. on the side of a volcanic mountain) such that ground level is regularly exposed to clouds passing by.  
> **username_0**: Thank you, @username_2 I will ask the question there, and put in the details mentioned in the other comments as well.  
> **username_4**: @username_2 Agreed: this is *exactly* the kind of question that the worldbuilding SE exists for. It took some discussion in meta.earthscience even to agree that (real, observable) non-Earth planets can be on-topic here -- imaginary worlds would definitely be a step too far! (But I can't resist mentioning in passing that, in a densely inhabited city, [smog](http://en.wikipedia.org/wiki/Great_Smog) would appear to fit the questioner's requirements rather neatly.)  
> **username_0**: @username_4 It would... except that it is a fantasy world, and so smog is not present. I didn't realize the World Building Beta existed when I asked this, which is why I put it here. Sorry about that.  
> **username_5**: The question is now on [Worldbuilding](http://worldbuilding.stackexchange.com/questions/9013/how-can-i-keep-dense-fog-in-an-area-for-half-a-day).  
> **username_6**: Although the context for the question is a fictional world, it is still relevant to the natural world. The city could also be in a low-lying area where the valley 'fills' with fog and I believe that would be more conducive to regular persistent fog than on the side of a mountain. Conceivably could be subject to coastal fog like San Francisco.  
> **username_4**: @username_0 I wouldn't have thought "fantasy world" *per se* necessarily precludes smog (you can find smog in e.g. *The Lord of the Rings*). But of course in your own world you make the rules, and this kind of arbitrary constraint is exactly what pushes it out of Earth Science territory. But I see you're getting good answers already over on worldbuilding, so good luck finding something that fits the bill!  
> **username_7**: @username_0 crossposting is discouraged.  In the future if you feel your question is better suited for a different stackexchange site, you can flag your question for migration to that site.  
> **username_8**: @username_0: You could edit this question to be on-topic on this site, and keep the WorldBuilding.SE question as is. Something along the lines of *"Are there any parts of the world that regularly have fog until late morning, and if so, what factors cause that phenomenon?"* or just *"What causes late-morning fogs?"* would be pretty on-topic, and would complement this question on WB.SE.  

---

## 1 answers

### Answer by username_9 on 2015-01-21. Score: 2

The heat of the Sun can "burn off" fog. So a lack of direct sunshine, cool temperatures & humidity (evaporation of water from a nearby body of water or saturated or wet ground) are key to maintaining fog. The air must be moist!


---

