PMW Optimizations

PMWeather Optimizations 1.2.1

PMWeather Optimizations is a server-only mod designed to improve TPS and make higher player counts more playable.

Built for ProtoManly’s Weather 0.16.4 on Minecraft 1.21.1.

Chunk and Surface Processing

Reduces PMWeather’s expensive chunk scanning while preserving wildfire, scorching, extinguishing, thermal shock, and dead-log behavior.

Modified Precipitation Budget

Limits optional PMWeather precipitation work per level to prevent large weather events from overwhelming the server thread.

Biome and Chunk-Loading Protection

Uses already-loaded chunk and biome data wherever possible, preventing precipitation checks from generating or synchronously loading missing chunks.

Precipitation Optimizations

Reuses repeated precipitation calculations and skips atmospheric values that are not needed by the precipitation system.

Rain Query Caching

Caches identical isRainingAt checks during the same server tick, reducing repeated PMWeather rain calculations.

Wind Optimizations

Reduces unnecessary terrain collision rays, duplicate heightmap queries, cyclone calculations outside their effective range, and repeated fire-intensity lookups.

Entity Wind Safety

Entity movement and wind effects remain entirely on the Minecraft server thread. No entities are asynchronously ticked or modified.

Moisture Networking

Sends moisture and fire updates only to players already tracking the affected chunk.

Smaller Optimizations

Reuses storm identifiers and removes several repeated object allocations and lookups.

Experimental Thermodynamic Optimization

Disabled by default.

This feature is purely experimental and has shown a regression in TPS during testing. It should not be enabled by default or treated as a recommended performance improvement.

It remains available only for additional testing and development.

Experimental Multithreading

Disabled by default.

Experimental atmospheric calculation workers are available only when both multithreading and thermodynamic optimization are manually enabled.

The server thread never waits for worker results, and all live Minecraft world access remains on the server thread.

Because the thermodynamic system currently shows a TPS regression, experimental multithreading is also not recommended for normal servers.

Runtime Controls

All commands require Minecraft permission level 2 aka OP only:

/pmw-optimizations on
/pmw-optimizations off
/pmw-optimizations status

/pmw-optimizations thermodynamic on
/pmw-optimizations thermodynamic off
/pmw-optimizations thermodynamic status