Rainfall

Rainfall is a dynamic weather simulation mod that transforms Minecraft’s rain into a fully interactive water system.

Instead of simple visual rain, precipitation accumulates on surfaces, forming realistic puddles that grow over time. Water spreads based on terrain shape, collects in low areas, and gradually develops into flowing streams that follow natural slopes. These streams can merge, create small runoff paths, and visually connect different water bodies, all without altering or destroying blocks.

The system is designed to be performant while still delivering detailed and immersive behavior. It simulates water flow, surface spread, evaporation, and drainage in a way that feels natural and responsive to the environment.

For debugging and visualization, a built-in debug renderer is available.
Press P to toggle the debug view, which displays internal simulation data such as flow directions, basins, and water distribution.