The Beaufort Wind Scale

It is often said that Francis Beaufort, of the British Royal Navy, was the first to devise a scale of wind force — towards the start of the 19th century. In fact, Beaufort did not really develop something new; but he did eventually succeeded in getting others to adopt his scale as a standard when there was no existing standard, primarily due to his position as British Admiralty Hydrographer of the Navy (which he held for 25 years).

A century earlier, in a book written in 1704 entitled The Storm: or, a Collection of the most Remarkable Casualties and Disasters which happened in the late Dreadful Tempest, both by Sea and Land, Daniel Defoe (who also wrote Robinson Crusoe), described a twelve-point "table of degrees" used by sailors of that day.

In 1801, Colonel Capper of the East India Company, in Observations on the winds and monsoons, reproduced “A table of the different velocities and forces of the winds, constructed by Mr Rous, with great care, from a considerable number of facts and experiments”.

Francis Beaufort devised his scale of wind force in 1805, when serving aboard HMS Woolwich. He first mentioned it in his private log on 13 January 1806, stating that he would, “hereafter estimate the force of the wind according to the following scale”. For many years, Beaufort’s scale of wind force was used only in his private logs. There is no mention of it in the official logs of HMS Woolwich or any other ships on which he served. The first published reference to Beaufort’s scales of wind force came in 1832, when the Nautical Magazine carried an article entitled “The Log Board”. A few years later, in December 1838, the Admiralty of the British Royal Navy dictated that all ships should keep hourly weather records, and should indicate the wind using the scale devised by Beaufort.

The initial criteria used for the scale was based on the canvas carried by a sailing ship at various wind speeds. For example, the criterion for Category 10, Whole Gale, was “With which she could only bear close-reefed maintop-sail and reefed fore-sail”. As dependence on sails waned, the Beaufort Scale was revised; and finally, in 1906, British Meteorologist George Simpson proposed the criteria should be the appearance of the sea at the various wind speeds. This modified Beaufort Scale was adopted by the International Meteorological Organization in 1939.

Following is the Beaufort Wind Scale in its current form, which now includes criteria for observations on land.

(UK) National Meteorological Library and Archive Fact Sheet 6 — The Beaufort Scale (pdf)

Howtoons — The Beaufort Scale (source for the pictures)

The Storm by Daniel Defoe (ebook)