If you build a 1x1 tower in snowy biomes and build until y=93 then set weather to rain, It will snow on top of the tower but not other areas. Also, if you stand directly above the 1x1 tower, you'll no longer see it.

Steps to Reproduce:

1. Build a 1x1 tower until you reached y=93

2. Use /weather rain

3. The snow will appear and if you break the topmost block the snow will no longer appear