Why not make it rain/snow in biomes at different times? As it currently stands when it rains in a world it rains/snows in every possible biome. Why not make it snow/rain at different times?
On top of this, why not make the precipitation different for each biome? Say, jungles would have a MUCH harder downpour than say just a normal forest, and Ice Plains and Ice Spikes might snow harder than on extreme hills (or vice versa), or just weather in general I think could be touched up on a bit. As it stands it's pretty bland and just quite frankly just annoying.
Personally I think the survival aspect of the game would be a lot better with the above suggestions.