Flight Changi Airport departs from Singapore Changi Airport at 20:30 and arrives at Sydney Sydney Airport at 07:25.
The flighttime is about 7h 55m. The distance travelled ("as the bird flies"): 5577 Km. So the average speed is roughly 704 Km.
There is an 3 hour time difference between Singapore and Sydney
The best day to arrive at Singapore is Sunday and it would be best to avoid Thursday, as prices are on average 149.98% higher than on Sunday. (Average prices, based on 601912 datapoints.)
We have a lot more statistics for flights BA 7494 and between Singapore and Sydney.