Has anyone here visited theme parks in China and know what the go is for there coaster operations when it’s raining? I leave next week and am looking at going to happy valley and chimelong in Guangzhou but the weather isn’t looking good so if anyone has been to these when it’s been raining I’d love your input. 

We had a slightly damp day at Happy Valley Shanghai back in 2016, coasters operated as normal in light rain. Heavy rain or lightning might be a different story. But in general they seemed more like the European parks than say, Japan (where a light sprinkle is often enough to pause operations).

I can't answer your question, but I'd be interested to hear about your visit to Chimelong when you return. Was going to visit during my Hong Kong trip last year but had to skip it

As @aaronm stated above light rain seems to be OK, but heavy rain or lightning and they stop.

 

I visited Happy Valley in Beijing in 2010 on a miserable day and the coaster operations were sporadic depending on how heavy the rain was. Additionally (Not sure if Happy Valley Guangzhou does the same) the coasters were on a rotating schedule, some opened with the park, others opened later in the day while the early opening ones closed.