It feels odd that cold-ish biomes plugins, mods and etc. add dont really have frosty breath, it would be a nice feature to being able to configure which biomes would have it

Curious, since it isn't intended to be only vanilla biomes. The only biome requirement is that the biome is cold enough to snow instead of rain. Could you give me an example of a mod that it isn't working in?

I was thinking like when a biome seems very suitable to have snowy breath but the temprature is too high for it to happen

Oooh, I misunderstood, you want to be able to add the effect non snowy biomes that seem like they should be cold enough for it. Yeah I can do that