Flight Changi Airport departs from Singapore Changi Airport at 23:20 and arrives at Tokyo Narita International Airport at 07:10.
The flighttime is about 6h 50m. The distance travelled ("as the bird flies"): 4385 Km. So the average speed is roughly 642 Km.
There is an 1 hour time difference between Singapore and Tokyo
The best day to arrive at Singapore is Wednesday and it would be best to avoid Sunday, as prices are on average 144.22% higher than on Wednesday. (Average prices, based on 815920 datapoints.)
We have a lot more statistics for flights TR 808 and between Singapore and Tokyo.