The question Most efficient method of storing energy with water on the moon? proposes a several hundred meeter tall subsurface cavern on the Moon. I added the following comment to an answer:
I keep thinking that there should be some way to use liquid/solid phase change as a way to store energy but I am bad at thermodynamics. Lunar subsurface temperatures are about 255 K near the surface and increase about 1.5 K per meter in depth (from here) so there are various temperatures above and below 273 K available in the walls of your 200 meter deep cavern if one did a little drilling. Who knows, it might be liquid at the bottom, and assuming the cavern is sealed and with evaporation there could even be rain!
Assuming the following:
- the cavern was sealed so that an equilibrium vapor pressure were established
- the floor was deep enough to expose the water to temperatures above the freezing point of water (273 K)
- the ceiling was high enough to expose the water vapor to temperatures well below the freezing point of water
Question: Would there be continuous rainfall or snowfall inside? Would there be fog or clouds?