Beaufort scale

American  

[boh-fert] / ˈboʊ fərt /

noun

1. a scale of wind forces, described by name and range of velocity, and classified as from force 0 to force 12, or, sometimes, to force 17.

2. a scale of the states of sea created by winds of these various forces up to and including force 10.

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Beaufort scale British  

noun

1. meteorol an international scale of wind velocities ranging for practical purposes from 0 (calm) to 12 (hurricane force). In the US an extension of the scale, from 13 to 17 for winds over 64 knots, is used

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Beaufort scale Scientific  

/ bō′fərt /

1. A scale for classifying the force of the wind, ranging from 0 (calm) to 12 (hurricane). A wind classified as 0 has a velocity of less than 1.6 km (1 mi) per hour; a wind classified as 12 has a velocity of over 119 km (74 mi) per hour. Other categories include light air, five levels of breeze, four levels of gale, and storm. The scale was devised in 1805 as a means of describing the effect of different wind velocities on ships at sea. It is named after an admiral in the British navy, Sir Francis Beaufort (1774–1857).

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Etymology

Origin of Beaufort scale

1855–60; named after Sir Francis Beaufort (1774–1857), British admiral who devised it

Example Sentences

Fanned by gale-force winds reaching up to eight on the Beaufort scale, the flames have spread rapidly southward, threatening homes, tourist accommodation, and critical infrastructure, including a fuel station.

From BBC • Jul. 2, 2025

On its website, it said its general view was "that damage can occur even when the wind speed is lower than level 10 on the Beaufort scale", which starts at 48 knots, or 55mph.

From BBC • Dec. 15, 2024

Even the Beaufort scale, which measures wind speed, categorises it specifically in relation to its impact on objects.

From The Guardian • Oct. 15, 2017

A heavy storm is a nine or a ten on the Beaufort scale, so the alarm sounds at Beaufort force 8.

From The New Yorker • May 16, 2016

Hurricane is the strongest force of wind in the Beaufort scale.

From Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 8 "Hudson River" to "Hurstmonceaux" by Various