Weather stone
A magic stone that appears somewhere in your town, but only if you have installed both of these expansions pack: The Sims 3: Supernatural and The Sims 3: Seasons.
The stone can be used by supernatural sims like vampires or fairies to change the weather in your town, if successful...
This was confirmed on this video by the The Sims crew at the 9th of October 2012 ( at 20 min in the video).
[http:// www.origin.com/maxis-live]