I recently asked a question about how a world could have permanent cloud cover. The answer was to turn the world into venus.

However, my purpose for cloud cover was to have the people living above it not be able to see the surface when they look down. Venus' clouds extend quite a ways, to the point where anything above them is simply too high up to support life. Therefore, I need to bring the life much closer to the surface.

I still want the surface completely and permanently covered by fog or low clouds. How can I do this?


  • If possible, I want my people to be above the clouds, not in them.
  • The surface of the planet does not matter; you can do anything you want to it to achieve the fog/clouds.
  • The setting is medieval/fantasy, so everything has to occur naturally.

You get fog when you have moist air that is cooled below the dew point, causing water droplets to condense on particulate in the air (basically). For persistent fog over a large geologic area, you could have a large swamp/marsh system fed by artesian spring water. Since it would come from deep within the planet it would be cool and thus cool the surrounding air. Add a humid source of air, wind from over a body of water or hand waving just more moisture in the atmosphere and you get fog.

A similar effect could be achieved with moist air experiencing a change in altitude like the rain shadow. If you have the setting just right you would just get the clouds and no rain.

Neither could really cover a planet, but if the setting is medieval/fantasy it could certainly cover an area so large as to be considered the whole planet.

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    $\begingroup$ You might consider making the 'high habitable living area' a plateau, which would limit the ability of inhabitants to observe lowlands other than those surrounding them (without traversing the hostile lowlands to go see). $\endgroup$ – Mark Ripley Mar 11 '17 at 11:14
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    $\begingroup$ @MarkRipley or even multiple plateaus, the inhabitants thinking they're floating islands created by some god of their culture. XD $\endgroup$ – Garrett Gaddy Mar 12 '17 at 0:59

Make volcanoes that create fog, but the locals will live above the maximum limit the fog can rise. Problem solved.

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    $\begingroup$ How do the volcanoes create fog? What is the limit? $\endgroup$ – Thomas Reinstate Monica Myron Mar 10 '17 at 22:13
  • $\begingroup$ Hi, Welcome to worldbuilding. It seems you have an idea of how to answer this question however, on the whole, it helps if you add a little more detail to how the processes you have in mind will work. $\endgroup$ – Lio Elbammalf Mar 10 '17 at 22:42

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