Flight Changi Airport departs from Singapore Changi Airport at 11:45 and arrives at Taipei Taoyuan International Airport at 16:40.
The flighttime is about 4h 55m. The distance travelled ("as the bird flies"): 2134 Km. So the average speed is roughly 434 Km.
The best day to arrive at Singapore is Monday and it would be best to avoid Thursday, as prices are on average 46.07% higher than on Monday. (Average prices, based on 665970 datapoints.)
We have a lot more statistics for flights SQ 878 and between Singapore and Taipei.