Minecraft | Swap rain for snow?

Is there a possibility in an already existing world (1.16.3) to exchange the rain with snow e.g. With a command or something similar?

Or maybe there's also a mod or addon for?

Would be grateful for helpful answers!

No, for that you have to change the biome and that works as far as I'm only on one server

I own a server. How can you do that?

Look at this

As far as I remember it occurs in it