weather

How surfaces respond to weather.

local weather = require("@builtin::systems.weather.weather")

weather.set({ wetness = 0.8, snow = 0.0 })
weather.get()      --> the settings in force
weather.active()   --> is the pass running
weather.clear()    --> no weather, settings kept

set takes any subset. With both wetness and snow at 0 nothing is falling and the pass is released.

Three things decide what a surface gets: which way it faces, whether it is sheltered, and how much weather there is. shelter at 1 leaves anything under cover completely dry; at 0 the world is wetted evenly regardless of what is above it.

snowBias is how steeply a surface must face up before snow settles. Unlike rain, snow either lies or it does not, so it is a threshold rather than a ramp.

For weather a scene should simply have, author the Weather component instead. This module is for code driving weather over time — a storm cycle, a scripted downpour.

The full description is in the package readme: guides { path = "systems/weather" }.