The only canon reference to speed that I’ve been able to derive comes from the Saiyajin series.
The snake way has 1 million kilometres and it takes Goku between 1 day and 4 hours and 2 days to complete his way back. That will give us a sustainable speed of, at minimum, 5km per second, with his sprinting speed being probably higher.
This is on a fairly early point of his development. Is there any further canon reference (either direct or derived) on any media that state his speed later on the series?