Flight Changi Airport departs from Singapore Changi Airport at 05:20 and arrives at Shenzhen Shenzhen Bao'an International Airport at 09:35.
The flighttime is about 4h 15m. The distance travelled ("as the bird flies"): 1318 Km. So the average speed is roughly 310 Km.
The best day to arrive at Singapore is Wednesday and it would be best to avoid Thursday, as prices are on average 237.16% higher than on Wednesday. (Average prices, based on 131208 datapoints.)
We have a lot more statistics for flights CZ 5086 and between Singapore and Shenzhen.
