Flight International Airport departs from San Francisco International Airport at 11:30 and arrives at Singapore Changi Airport at 19:10.
The flighttime is about 16h 40m. The distance travelled ("as the bird flies"): 15083 Km. So the average speed is roughly 905 Km.
There is an 15 hour time difference between San Francisco and Singapore
The best day to arrive at San Francisco is Thursday and it would be best to avoid Sunday, as prices are on average 258.7% higher than on Thursday. (Average prices, based on 21857 datapoints.)
We have a lot more statistics for flights SQ 31 and between San Francisco and Singapore.