Thx :D. No, that was not the idea xD... it works quite well in some cases (of wind direction and wind direction change), but in some others I really have to give it a second look. It's just that this kind of particle simulation took me so long to get it done efficiently (without iterating through all pixels each iteration) that unfortunately there just wasn't enough time for some other things such as cloud spawning, sounds etc.
Yes the cpu power has a really high impact. In fact I'm glad it runs with 60 fps in the browser, as it runs with around 8000 FPS on my desktop pc but only with around 400 FPS on my laptop, so I was afraid it would be unplayable in the browser ^^