At that time naval officers made regular weather observations, but there was no scale and so they could be very subjective - one man's "stiff breeze" might be another's "calm conditions". The initial scale from zero to 12 did not reference wind speed numbers, but related qualitative wind conditions to effects on the sails of a man of war, then the main ship of the Royal Navy, from "just sufficient to give steerage" to "that which no canvas [sails] could withstand." The scale was made a standard for ship's log entries on Royal Navy vessels in the late 1830s.

The scale was adapted to non-naval use from the 1850s, with scale numbers corresponding to cup anemometer rotations. In 1906, with the advent of steam power, the descriptions were changed to how the sea, not the sails, behaved and extended to land observations. Rotations to scale numbers were standardized only in 1923, and land-based descriptors were also added. The measure was slightly altered some decades later to improve its utility for meteorologists.

The Beaufort scale was extended in 1946, when Forces 13 to 17 were added. However, Forces 13 to 17 were intended to apply only to special cases, such as tropical cyclones. Nowadays, the extended scale is only used in Taiwan and mainland China, which are often affected by typhoons.

Wind speed on the 1946 Beaufort scale is defined by the empirical formula:

v = 0.836 B^3/2 m/s

where v is the equivalent wind speed at 10 meters above the surface and B is Beaufort scale number. For example, B = 9.5 is related to 24.5 m/s which is equal to the lower limit of "10 Beaufort".