Clue: 0 or 1, then 10 — or, on the face of it, 3,4,6, then 7? (4,6,3,5)
Answer: CALM BEFORE THE STORM
Explanation: Definition: 0 or 1, then 10
The Beaufort scale: CALM ('0 or 1' – 1 is actually light air) BEFORE ('then') THE STORM ('10'); then essentially the same repeated in terms of clue answers – although CALM for "'on the face of it', BUTTER WOULD'NT MELT IN HIS MOUTH" seems to me a bit of a stretch, though I think I get the idea that such a person's face would show calm.