Very interessting pick of the theme. This is a really nice sumlator that you've created. I thought I could stop the fire by spamming rain. Well clicking them too often so that the clouds turn black wasn't that helpful :-P.
You did very well on the effects - specially when everything is burning it looks really dramatic. Also I like the how-to-play. The game is explained very well also with images. Thats really good!
One thing that I would add is a settings menu so that the player can control the audio.
So I'd say you did a really good job here.