Pokémon Black Version Easter eggs

Diamond Dust
On rare occasions, when visiting Icirrus City, instead of seeing the snow falling like normal, you will instead see a different kind of weather condition, similar to snow called Diamond Dust. This weather condition is very rare and can only be found specifically in Icirrus City on New Years' Eve.

Diamond Dust also makes appearances on the top of Mt. Silver in HG/SS and in Snowpoint City in D/P/Pt.