Flight Changi Airport departs from Singapore Changi Airport at 03:55 and arrives at Guangzhou Guangzhou Baiyun International Airport at 08:20.
The flighttime is about 4h 25m. The distance travelled ("as the bird flies"): 1282 Km. So the average speed is roughly 290 Km.
The best day to arrive at Singapore is Thursday and it would be best to avoid Saturday, as prices are on average 1104.62% higher than on Thursday. (Average prices, based on 314950 datapoints.)
We have a lot more statistics for flights CZ 8490 and between Singapore and Guangzhou.