Flight Changi Airport departs from Singapore Changi Airport at 22:00 and arrives at Seoul Incheon International Airport at 05:35.
The flighttime is about 6h 35m. The distance travelled ("as the bird flies"): 2923 Km. So the average speed is roughly 444 Km.
There is an 1 hour time difference between Singapore and Seoul
The best month to arrive at Singapore is February and the most expensive month to fly is July. (Average prices, based on 368 datapoints.)
The best day to arrive at Singapore is Tuesday and it would be best to avoid Sunday, as prices are on average 461.56% higher than on Tuesday. (Average prices, based on 997608 datapoints.)
We have a lot more statistics for flights GA 644 and between Singapore and Seoul.