Sega's NiGHTS: Journey of Dreams will be the first game for the Wii that makes active use of the Wii Weather system. In other words, the actual weather outside will effect the game play for the first time. The game takes place in a dream world, and in the "My Dream" area, which is already heavily customizable, there will be the opportunity to make use of the actual weather for flying conditions.
The game is supposed to be all about facing fears through conquering them in your dreams. The way we see it, the real fears are the ones that are tied to real life things, as opposed to the relative escape of your dream world. But we're old and bitter, and this is likely to be fun. And weathery!
NOTE: We seem to remember that Madden for the Wii had this function, but the press release for this game says that it's the first, so who you gonna believe?