Flight Changi Airport departs from Singapore Changi Airport at 01:45 and arrives at Hong Kong Hong Kong International Airport at 05:50.
The flighttime is about 4h 05m. The distance travelled ("as the bird flies"): 1322 Km. So the average speed is roughly 324 Km.
The best day to arrive at Singapore is Sunday and it would be best to avoid Monday, as prices are on average 616.1% higher than on Sunday. (Average prices, based on 2265094 datapoints.)
We have a lot more statistics for flights OM 5732 and between Singapore and Hong Kong.