How to set snow weather on biomes other then snowy

I am trying to make a plugin so you can set when it snows out along with rain by command.

I can't set it to snow unless it is a snow biome. I was thinking to get all the biomes in the world, turn them into a snow biome then use setStorm(true). That seems like it would cause a lot of lag then it would be a pain to undo it... Anyone know a simpler way to do this?