Flight Hong Kong International Airport departs from Hong Kong Hong Kong International Airport at 08:00 and arrives at Singapore Changi Airport at 11:55.
The flighttime is about 3h 55m. The distance travelled ("as the bird flies"): 1322 Km. So the average speed is roughly 338 Km.
The best month to arrive at Hong Kong is February and the most expensive month to fly is July. (Average prices, based on 2565 datapoints.)
We have a lot more statistics for flights GA 691 and between Hong Kong and Singapore.