This is a mirror of Immersive Snow, by Straywave. I have permission to reupload this content. Find the main page here.

Features:

Snow recalculation upon chunk loading. No more winter chunks in the summer!
Changing day cycle duration depending on the season. Longer nights in the winter.

Compatibility:

Hourglass integration requires Forge and Serene Seasons. It will overwrite your daySpeed and nightSpeed to match the current season, however you can set a hourglassDaySpeed / hourglassNightSpeed in the configuration file if you wish. If you want, you can disable it entirely in the configuration. (Hourglass for 1.16.5 is on CurseForge)

Performance:

In 1.1.0, performance was significantly increased by only updating blocks when they need an update (i.e. grass blocks). Also, call to Biome.shouldFreeze has been removed, as it was a major source of lag and always returned false anyway.

As a coarse benchmark (totally unscientific), after flying around and generating chunks in Creative, the mod only used 0.99% of the Server Thread according to Spark Profiler.