Weather

It would be really awesome to have a weather option. You could select rain, thunder, snow. With rain, it would path trace reflective ground. With snow, it would be foggier and light would be "absorbed more" You could also add a lightning strike if you wanted to the background that would have lighting properties. I think this could be a really awesome feature to add.

The issue names no files, tests, or entry points. First map the rendering and scene-configuration areas, then clarify the scope of selectable rain, thunder, and snow effects and how each should appear before implementation; done should include agreed behavior and coverage for the selected weather modes.

Written by the indexing model from the issue text.