Please select your home edition
Edition
Doyle_SailWorld_728X90px_SY TOP

Beaufort Scale - wind and sea conditions

by Nancy Knudsen on 12 Apr 2010
There we were... SW
'..so there we were in a Force 8..'

'A what?'

'..a Force 8, and the winch jammed...'
'
What's a Force 8 mate?'

'It's a bloody big wind - where do you come from?'

'Australia.'

'I see old chap - that explains it. Now can I get on with my story?'


The Beaufort scale has long been a bit of a mystery to those who don't have occasion use it very often, and, as many forecasts from certain parts of the world are given using the Beaufort Scale, if you're not familiar with it, it's a good idea to have the translation pasted up above the chart table.

The scale was created in 1805 by, surprise surprise, Sir Francis Beaufort, an Irishman who became a British admiral.

He created the scale to attempt to standardise the descriptions that naval officers made to each other, and eliminate subjectivity. This was so successful that by the 1830's the standard was accepted throughout the Royal Navy.

The Beaufort Scale describes in a visual way the Sea State and relates that back to wind speed.

Usually, this works (not always) the sea state can be associated with certain wind strengths. It is most accurate in an open ocean, and particularly when the sea is well developed by the present wind, so the Beaufort scale numbers are traditionally associated with a certain range of wind speed.

However, a rapid wind change or an area of little fetch, will naturally not provide an alignment between the visual sea state and the wind strength.

Here's a brief summary of the scale, with accompanying wind speed:

 

Beaufort number Description
 
Wave height Sea conditions


Knots Metres Feet
0 Calm < 1 0 0 Flat.
1 Light air 1 – 2 0 – 0.2 0 – 1 Ripples without crests.
2 Light breeze 3 – 6 0.2 – 0.5 1 – 2 Small wavelets. Crests of glassy appearance, not breaking
3 Gentle breeze 7 – 10 0.5 – 1 2 – 3.5 Large wavelets. Crests begin to break; scattered whitecaps
4 Moderate breeze 11 – 15 1 – 2 3.5 – 6 Small waves with breaking crests. Fairly frequent white horses.
5 Fresh breeze 16 – 20 2 – 3 6 – 9 Moderate waves of some length. Many white horses. Small amounts of spray.
6 Strong breeze 21 – 26 3 – 4 9 – 13 Long waves begin to form. White foam crests are very frequent. Some airborne spray is present.
7 High wind, Moderate gale, Near gale 27 – 33 4 – 5.5 13 – 19 Sea heaps up. Some foam from breaking waves is blown into streaks along wind direction. Moderate amounts of airborne spray.
8 Gale, Fresh gale 34 – 40 5.5 – 7.5 18 – 25 Moderately high waves with breaking crests forming spindrift. Well-marked streaks of foam are blown along wind direction. Considerable airborne spray.
9 Strong gale 41 – 47 7 – 10 23 – 32 High waves whose crests sometimes roll over. Dense foam is blown along wind direction. Large amounts of airborne spray may begin to reduce visibility.
10 Storm, Whole gale 48 – 55 9 – 12.5 29 – 41 Very high waves with overhanging crests. Large patches of foam from wave crests give the sea a white appearance. Considerable tumbling of waves with heavy impact. Large amounts of airborne spray reduce visibility.
11 Violent storm 56 – 63 11.5 – 16 37 – 52 Exceptionally high waves. Very large patches of foam, driven before the wind, cover much of the sea surface. Very large amounts of airborne spray severely reduce visibility.
12 Hurricane = 64 = 14 = 46 Huge waves. Sea is completely white with foam and spray. Air is filled with driving spray, greatly reducing visibility.
Allen Dynamic 40 FooterTrofeo Princesa Sofía Mallorca 2025Lloyd Stevenson - AC ETNZ 1456x180px BOTTOM

Related Articles

Engedinwing 2025 WingFoil Racing World Cup preview
The world's most daring wingfoilers are heading for the heights... literally The world's most daring wingfoilers are heading for the heights - literally - as the Ensis ENGEDINWING 2025 WingFoil Racing World Cup Switzerland descends on lake Silvaplana.
Posted today at 9:19 am
Diverse maxi fleet ready for Loro Piana Giraglia
Inshore/coastal racing prior to the event's famous offshore race to Genoa The International Maxi Association's 2025 Mediterranean Maxi Inshore Challenge (MMIC) continues tomorrow, Saturday 7 June with the first of four days of inshore/coastal race of Loro Piana Giraglia, organised by the Yacht Club Italiano
Posted today at 9:04 am
Marine Auctions: June online auctions
Bidding to open on Friday 20th June The Bidding for the June Online Auction will commence on Thursday 20th June and will end on Thursday 26th June at 2pm AEST.
Posted today at 5:19 am
2025 Santa Maria Cup in Annapolis, USA Day 3
Nicole Breault and Allie Blecher to meet in the final USA's Nicole Breault / Vela Racing and Allie Blecher / Team Baam have both advanced to the final of the Santa Maria Cup in Annapolis, the second stage of the 2025 Women's World Match Racing Tour championship.
Posted today at 4:48 am
Scandinavian Gold Cup at Sopot, Poland Day 2
Three boats are now through to the final stage Three boats are now through to the final stage of the Scandinavian Gold Cup in Sopot, Poland. Aspire, Marie-Françoise XXII and Artemis (NOR 57, Kristian Nergaard, Johan Barne Trond, Solli-Sæther) have each won one race each.
Posted today at 1:48 am
49er, 49erFX and Nacra 17 Europeans Day 4
Bergmann with Wille keep their nerve to move into FX lead Olympic veterans in the 49erFX Marla Bergmann with Hanna Wille (GER) kept their nerve and used their speed to move into the lead, scoring the fewest points on day 4.
Posted on 6 Jun
Windies Multihull Trophy winners announced
Thirty multihulls competed across eighteen events from Barbados to the British Virgin Islands. With the conclusion of the 2025 season, the Caribbean Sailing Association's Budget Marine Windies Multihull Trophy results are in!
Posted on 6 Jun
Galicia 52 Super Series Royal Cup Day 4
Hutchinson adding the missing element as American Magic Quantum Racing close in on title Now holding a 13-points lead after today's two races contested at the Galicia 52 Super Series Royal Cup, American Magic Quantum Racing crew are on the cusp of completing their first 52 SUPER SERIES regatta win since victory in Barcelona in September 2022.
Posted on 6 Jun
Emirates GBR looking to bounce back
At the Mubadala New York Sail Grand Prix this weekend Emirates GBR Driver Dylan Fletcher said the team was "looking to bounce back" at the Mubadala New York Sail Grand Prix this weekend, following a "tough time" at the back-to-back US events in LA and San Francisco in March.
Posted on 6 Jun
BVI Spring Regatta & Sailing Festival 2026 dates
The event has moved forward a week from previously published dates For 2026, the BVI Spring Regatta & Sailing Festival has moved the event forward a week from previously published dates to March 23-29.
Posted on 6 Jun