Flight Changi Airport departs from Singapore Changi Airport at 09:35 and arrives at Sydney Sydney Airport at 19:15.
The flighttime is about 7h 40m. The distance travelled ("as the bird flies"): 5577 Km. So the average speed is roughly 727 Km.
There is an 2 hour time difference between Singapore and Sydney
The best day to arrive at Singapore is Sunday and it would be best to avoid Friday, as prices are on average 290.63% higher than on Sunday. (Average prices, based on 405954 datapoints.)
We have a lot more statistics for flights SQ 211 and between Singapore and Sydney.