Flight Achmad Yani International Airport departs from Semarang Achmad Yani International Airport at 16:05 and arrives at Singapore Changi Airport at 19:00.
The flighttime is about 1h 55m. The distance travelled ("as the bird flies"): 760 Km. So the average speed is roughly 397 Km.
There is an 1 hour time difference between Semarang and Singapore