Rain in the real world and GURPS MAGIC

[Varyon]

Originally Posted by Emerikol

I would consider the rain spell as using what is already available in the atmosphere. Even in a desert there is likely water available if you had the technology to force it out. Or the magic.

Whereas create water is literally creating water from nothing or at minimum pulling it from another plane.

In one of the character vignette teasers leading up to the release of Diablo III, the Wizard (as a young girl) summoned rain to free a village from its drought, but was later driven out when the drought came back worse for her having depleted the region of most of its water in the process. I'd probably interpret a spell that summons rain similarly, particularly if it has the sort of energy efficiency we're talking about here (when compared to something that creates water ex nihilo).