Flight Hong Kong International Airport departs from Hong Kong Hong Kong International Airport at 00:20 and arrives at Singapore Changi Airport at 04:10.
The flighttime is about 3h 50m. The distance travelled ("as the bird flies"): 1322 Km. So the average speed is roughly 345 Km.
The best day to arrive at Hong Kong is Tuesday and it would be best to avoid Wednesday, as prices are on average 52.62% higher than on Tuesday. (Average prices, based on 2064585 datapoints.)
We have a lot more statistics for flights TR 975 and between Hong Kong and Singapore.