Hi Jo,
I knew that it was the scale for measuring wind, but I looked up google for a more specific answer:
The Beaufort scale is an empirical measure for describing wind intensity based mainly on observed sea conditions. Its full name is the Beaufort wind force scale.
Starting from 0 corresponding to calm, the Beaufort scale ascends to light air at 1, light breeze at 2, gentle breeze at 3, moderate breeze at 4, fresh breeze at 5, strong breeze at 6, near gale at 7, gale at 8, strong gale at 9, storm at 10, violent storm at 11, and hurricane at 12.
I think for my evening meal on the seafront I prefer it to be under 3 on the scale!!
Eileenxx