Flight Perth Airport departs from Perth Perth Airport at 18:00 and arrives at Singapore Changi Airport at 23:20.
The flighttime is about 5h 20m. The distance travelled ("as the bird flies"): 1789 Km. So the average speed is roughly 335 Km.
The best day to arrive at Perth is Friday and it would be best to avoid Saturday, as prices are on average 170.09% higher than on Friday. (Average prices, based on 269600 datapoints.)
We have a lot more statistics for flights TR9 and between Perth and Singapore.