Flight Changi Airport departs from Singapore Changi Airport at 05:15 and arrives at Guangzhou Guangzhou Baiyun International Airport at 09:25.
The flighttime is about 4h 10m. The distance travelled ("as the bird flies"): 1282 Km. So the average speed is roughly 308 Km.
The best day to arrive at Singapore is Sunday and it would be best to avoid Saturday, as prices are on average 1113.07% higher than on Sunday. (Average prices, based on 450091 datapoints.)
We have a lot more statistics for flights SQ 8430 and between Singapore and Guangzhou.
