Flight Changi Airport departs from Singapore Changi Airport at 16:05 and arrives at Hong Kong Hong Kong International Airport at 20:20.
The flighttime is about 4h 15m. The distance travelled ("as the bird flies"): 1322 Km. So the average speed is roughly 311 Km.
The best day to arrive at Singapore is Sunday and it would be best to avoid Thursday, as prices are on average 450.57% higher than on Sunday. (Average prices, based on 2245081 datapoints.)
We have a lot more statistics for flights QR 3491 and between Singapore and Hong Kong.