For the snow I'm suggesting a version of the map that has snow all over the roads, roofs and trees not an active snowfall weather addon. That way there wouldn't be frame drops, there would be no active snow dropping Infront of your screen like last winter.
I have this weather addon https://steamcommunity.com/sharedfiles/filedetails/?id=531458635 however I'm not sure if it would be any better for large server use. Anyhow at this point this suggestion post has mainly become making the server more winter esque during Christmas time since weather mods seem to be to much which is understandable.