Realism and  Efficiency 

The System is made within Blender's Geometry Nodes and uses no "real Physiks" based Simulations, instead relying on a curve-line-based system to recreate the movement of Rain and Snow. The Rain Drops / Snow Falkes can be changed if needed, but are already performance-oriented. The Scale of the Area where the Rain / Snow is falling is easy to adjust.

Easy to Use

All the Parameters of the System can be used without any deeper knowledge of Geometry Nodes and are made as user-friendly as possible. The Settings you will be able to control are: Rain / Snow Speed, Rain / Snow Density, Raindrop / Snowflake Size, Random Movment, Wind Direction, Height Start, Fog enable, Rain enable, Snow enable, Fog Height. 

Any Questions?

If you have any Questions regarding this System, feel free to contact me. At the Moment, there is no official Documentation for this Project as it is relatively self-explanatory regarding the use of its Parameters.