I bought a Best Weather Box from Xavier Novelli. (check it here) If you own a nature sim/parcel this weather is by far the best in all Second Life. You can choose between 3 different rains, thunder and 2 snows. And for a tiny price! The lightning effect and the sound add even more reality.
Very good for photographers and movie-makers.
It will be raining for a while on my building platform ♥