Flight Changi Airport departs from Singapore Changi Airport at 12:00 and arrives at Perth Perth Airport at 17:00.
The flighttime is about 5h 00m. The distance travelled ("as the bird flies"): 1789 Km. So the average speed is roughly 358 Km.
The best day to arrive at Singapore is Thursday and it would be best to avoid Sunday, as prices are on average 1955.5% higher than on Thursday. (Average prices, based on 225811 datapoints.)
We have a lot more statistics for flights TR8 and between Singapore and Perth.