Flight Changi Airport departs from Singapore Changi Airport at 17:50 and arrives at Guangzhou Guangzhou Baiyun International Airport at 22:00.
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 Thursday and it would be best to avoid Sunday, as prices are on average 103.2% higher than on Thursday. (Average prices, based on 316204 datapoints.)
This graph shows the distribution of prices found in the past years for this flight. (Average prices, based on 108 datapoints.)
We have a lot more statistics for flights CZ 3040 and between Singapore and Guangzhou.