Truthfully I would love to do this, but I'm not entirely sure the most efficient way to do it, and I'm sure there are more experienced coders out there that do.
Love the idea though
/support
Edit;
I would actually prefer the precipitation being a preference in the Event GUI, as in RayCasting would also be the toggle for allowing/disallowing precipitation.
Or maybe its own pref, but of course both would require actual game modification, which probably won't happen :c