Hi @Forstride,
Would it be possible to add an option to lock certain dimensions into a fixed, eternal dimension (e.g. always winter, always summer...) ?

If the per-dimension season only supports season-locking (e.g. a dimension either follows the global season cycle, or is locked into a fix dimension - there is only one season cycle), that would be fine.

I can help a bit with the code if needed, though I'll have to learn how SereneSeason works.

Thanks for considering !

By the way @Forstride, are PR fine with SereneSeasons' license ? Since it is not allowed to 'Share Adapted materials' ?

yes PRs are allowed

Nice ! I'll see what I can do.
I also saw that TAN was discontinued. Is there any plan to allow adapted material for TAN to allow a fork/continuation ?

no

Just gonna close this. No PR was made, and we're likely not gonna add it ourselves. Seasons work on a global timer, so it'd likely require too much overhauling, and it's just not worth it when it'd be a very niche feature.