Flight Sydney Airport departs from Sydney Sydney Airport at 21:50 and arrives at Hong Kong Hong Kong International Airport at 05:10.
The flighttime is about 9h 20m. The distance travelled ("as the bird flies"): 5599 Km. So the average speed is roughly 600 Km.
There is an 2 hour time difference between Sydney and Hong Kong
The best day to arrive at Sydney is Wednesday and it would be best to avoid Monday, as prices are on average 105.64% higher than on Wednesday. (Average prices, based on 27861 datapoints.)
We have a lot more statistics for flights CX 138 and between Sydney and Hong Kong.