Snow behaves unnaturally due to chunks being unloaded and loaded.
This leads to strange occurrences such as natural snow being encountered in the summer when revisiting a chunk that was last loaded in winter.

A potential solution to this would be to make natural snow melt the instant a chunk loaded a few days after it was "supposed" to start melting and all the way untill the day snow starts forming.

That way you won't encounter any natural snow in places that it does not make sense just because you haven't visited a chunk in a while.

Lemme know if it is possible.

Would it be worth triggering it on sleeping in a bed instead?
It's very strange having blocks of snow around your base in the middle of summer just because you went off adventuring at winter.
I understand it would be resource intensive to have a check for those blocks constantly but maybe just the areas loaded when you sleep in summer?
That way you can 'let the snow melt with the sunrise' in summer to save running around for an hour with shovels in an area you inhabit.

Oh, nice, never heard of it. I'll take a look at it and see if something like that can be implemented here. This mod is still being maintained although development has been on pause for the last few months.

This is a pretty old issue, but I thought I might mention just in case - there seems to be a mod that is able to do this, albeit in Forge 1.12. I haven't checked it out in-game myself, but I took a glance at the comments and its Issues page and no one's mentioning performance costs, so it's possible that they've found a way around that concern. Maybe it'd be worth taking a peek in case some of the code is applicable, if you're still maintaining this mod? Here's the link.

This would still be a really good addition to the mod. The snow covered chunk borders are really annoying and arent realistic.

Maybe instead of using snow layers you could add a snow texture on top of other block textures. You could use the sky light level to determine which blocks get affected. Doing so would eliminate issues with chunk borders and might allow for some cool patterns in the snow.

A good way to resolve this is to add an acceleration config option to how quickly a chunk adjusts to the current season. If the server admin / player wants to increase the responsiveness of the chunk adjusting, that option can be increased by the end user, speeding up the process of adjusting and putting the power in the end user's hands.

Instantly adjusting the chunks would be a bad idea. But speeding up the adjusting of chunks is configurable and performance friendly.

I don't think that's something I can reasonable do without significantly hurting performance. I will keep this issue here until I do some testing tho.