Why is the weather the only reason for the delay in flight cancellation of Air China?

well, it's definitely not just air China's flights that will be affected. It may be that Air China has more flights in the local area, so there are more flights affected, so it gives people the impression that Air China will cancel more flights. In addition, even if the origin and destination are the same, there will be cases where some companies can fly and some companies can't. There are generally two reasons for this. One is that when the weather is bad, there is a large backlog of flights. After the weather is good, planes have to queue up for take-off and landing, so if they queue up behind, they will have to wait for a long time. The other is that when the weather is bad, the coming plane can't come, so the return flight can't fly.