Flight Changi Airport departs from Singapore Changi Airport at 22:50 and arrives at Seoul Gimpo International Airport at 06:40.
The flighttime is about 6h 50m. The distance travelled ("as the bird flies"): 2961 Km. So the average speed is roughly 433 Km.
There is an 1 hour time difference between Singapore and Seoul
The best day to arrive at Singapore is Tuesday and it would be best to avoid Saturday, as prices are on average 87.49% higher than on Tuesday. (Average prices, based on 400342 datapoints.)
We have a lot more statistics for flights OZ 752 and between Singapore and Seoul.