I am sure I am not the first one to discover it. The rule is, if the wind blows from the east to the west, Shanghai is always as clear and beautiful. The visibility is very high, and I can see both Jinmao Tower, and the World Finance Center in Pudong from my office in Puxi. The wind from the east is from the Pacific Ocean, and it brings fresh air.
If the wind blows from west to east, Shanghai will be dirty and visibility is very low.
In most of the time, the wind in Shanghai blows from the north west to south east – as the wind of this latitude around the world, and the blue sky and clear sky in Shanghai is not as many as the bad time.
Anyone also observed the same thing?