Flight Changi Airport departs from Singapore Changi Airport at 20:50 and arrives at Shenzhen Shenzhen Bao'an International Airport at 01:00.
The flighttime is about 4h 10m. The distance travelled ("as the bird flies"): 1318 Km. So the average speed is roughly 316 Km.
The best day to arrive at Singapore is Monday and it would be best to avoid Thursday, as prices are on average 161.94% higher than on Monday. (Average prices, based on 72892 datapoints.)
We have a lot more statistics for flights CZ 8048 and between Singapore and Shenzhen.