The best month to fly between Perth and Sydney is February and the most expensive month to fly is May. (Average prices, based on 1249 datapoints.)
The best day to arrive at Perth is Saturday and it would be best to avoid Monday, as prices are on average 111% higher than on Saturday. (Average prices, based on 12675729 datapoints.)
The best time to fly is at around 5. (Average prices, based on 1408 datapoints.)