He starts out near the Fortress of Solitude, which is in Ellesmere Island. He then flies to Africa in a short timespan, with a prominent mountain in the background. Given that we see the sea dividing Africa and the Middle east later on it's safe to say he's in east Africa. So, for this I will be assuming he is near Mount Kilimanjaro.
Distance Flown (Minimum) - 10,675.75 km
Time Superman Begins Flying Horizontally - 2:04:98 (Technically a little before, but this is when he goes supersonic)
Time Superman Arrives in Africa - 2:13:37
13.37-4.98 = 8.39 s
10,675.75 km/8.39 s = 1,272,437.43 m/s
DCEU Superman's Day 1 Speed - Mach 3739.27, Massively Hypersonic+