Flight Hong Kong International Airport departs from Hong Kong Hong Kong International Airport at 20:25 and arrives at Singapore Changi Airport at 00:25.
The flighttime is about 4h 00m. The distance travelled ("as the bird flies"): 1322 Km. So the average speed is roughly 330 Km.
The best day to arrive at Hong Kong is Saturday and it would be best to avoid Tuesday, as prices are on average 321.1% higher than on Saturday. (Average prices, based on 2009104 datapoints.)
We have a lot more statistics for flights AY 5855 and between Hong Kong and Singapore.