Many planets don't have habitable surfaces, though at least Mercury has good temperatures underground (source: http://www.einstein-schrodinger.com/Mercury_temperature.pdf). So I'm wondering how large would a subterannean nature sanctuary building/dome height have to be, in order for it to have clouds and rain?
I'm thinking of NASA's Vehicle Assembly Building which purportedly develops rain clouds on humid days if the dehumidifiers aren't on, it is 160m tall, by 157x218m, and is 8 acres.
Particularly I'm wondering what the minimum height would be, and how that may relate to both gravity and air pressure. I.E. if it was 0.8atm and gravity is 3.7m/s^2 (0.38g), would that change the required dimensions than if it was a 1atm and 9.8m/s^2 (1g) ?
In terms of more naturalistic weather, I was wondering if it would make sense to have multiple such domes somewhat connected. And then could for instance raise the pressure in one, and lower it in another for wind. I don't know if using these pressure gradients it might be possible to form weather "fronts".
Also somewhat related is the worry that maybe it would use a lot of water, and those clouds might not "come down", Mercury is rather water scarce, so perhaps it would make sense to have an alternative irrigation method for the "nature sanctuaries". (I presume farming would be mostly stacked aeroponic, but humans would need nature sanctuaries to avoid cabin fever).