Originally Posted by
moondog
IME, SH is good from mid March onwards, while BJ shifts in early May. A third problem I forgot to mention about BJ spring is those annoying cotton_ball/pollen things. Apparently, the city has taken serious measures to replace the type of tree that is the culprit, but it's still unpleasant, to say the least. Basically, try to arrive in BJ after the trees are fully bloomed, and all will be good.
OK, so if I go to SH first, maybe mid-April and BJ afterwards, that might work? If its the trees I'm thinking of, I can deal with the pollen, but I'd like to avoid (regular) wet weather or weather that causes dust/haze. (I know there's no guarantees, just trying to go for the best odds).