In simple terms, the Beaufort scale is a standardized weather tool that allows mariners (and others) to estimate, describe, or predict conditions based on both the wind speed/strength and the accompanying sea conditions, in open waters.
Above: Wind and wave conditions like this might feel like a gale to one person and a storm to another. The Beaufort scale minimizes the confusion created by different interpretations of identical weather conditions. Photo courtesy of NOAA.
History Of The Beaufort Scale
The scale was introduced in 1805 by Irish-born Sir Francis Beaufort, a British Royal Navy officer who honed and refined an empirical system for estimating wind strengths without the use of instruments. In the 1830s, the Royal Navy officially adopted it. Eventually, the scale that bears Beaufort’s name became standard weather protocol for marine forecasters and sailors everywhere. In later years, descriptions of land conditions at various wind forces were added, to broaden the scope of the scale’s use.
Usage And Importance Of The Beaufort Scale
The beauty of Beaufort’s scale is that it uses standardized condition descriptions rather than an individual’s perception—since one man’s “gale” may be another man’s “fresh breeze.” While not every country still uses it today (including the United States, where surprising numbers of sailors have never even heard of it), in many countries it is still used for marine weather forecasts, among them the United Kingdom and Ireland, the Netherlands, Germany, Greece, Malta, China, Hong Kong, and Taiwan. In Greece, a destination that’s on the bucket list of almost every world cruiser and charterer, the Beaufort Scale is used exclusively, in all weather forecasts (marine and mainstream, including newspapers, radio, and television).
Understanding The Beaufort Scale For Mariners
Beaufort-based weather forecasts and advisories go something like this: “0900: Wind northeast, Force 6, rising to Force 7 by 1500 hours.” If you don’t know how that translates, you won’t find forecasts much help. For this reason, whether you’re dreaming of world cruising or simply planning to charter in foreign ports, learning the Beaufort scale—or having a handy table with you—is an absolute must in order to understand most local marine weather forecasts.
A Handy Reference Guide To The Beaufort Scale
Below is an abbreviated version of the Beaufort Scale, in chart form (land-condition descriptions have been omitted). You can either study and memorize it or print, clip, and save for quick and easy reference. May the force be with you!
| Beaufort Force | Wind Description | Wind Speed (knots) | Sea Conditions | Wave Height (meters)* |
| 0 | Calm | <1 | Flat calm. | 0 |
| 1 | Light air | 1 – 3 | Small ripples. | 0 – 0.2 |
| 2 | Light breeze | 4 – 6 | Small wavelets. Glassy crests. | 0.2 – 0.5 |
| 3 | Gentle breeze | 7 – 10 | Large wavelets. Some whitecaps. | 0.5 – 1 |
| 4 | Moderate breeze | 11 – 16 | Small waves. Breaking crests. | 1 – 2 |
| 5 | Fresh breeze | 17 – 21 | Moderate waves. Whitecaps, some spray. | 2 – 3 |
| 6 | Strong breeze | 22 – 27 | Long waves. White foam crests. Spray. | 3 – 4 |
| 7 | Near gale | 28 – 33 | Heaped seas. Breaking crests, foam streaks, airborne spray. | 4 – 5.5 |
| 8 | Gale | 34 – 40 | High waves. Breaking crests and spindrift/foam streaks. Airborne spray. | 5.5 – 7.5 |
| 9 | Strong gale | 41 – 47 | Very high waves with rolling crests. Dense foam. Airborne spray may reduce visibility. | 7 – 10 |
| 10 | Storm | 48 – 55 | Very high waves with overhanging crests and heavy impact. Sea surface white with foam. Reduced visibility from excessive spray. | 9 – 12.5 |
| 11 | Violent Storm | 56 – 63 | Exceptionally high waves. Large areas of white foam. Huge amounts of spray. Reduced visibility. | 11.5 – 16 |
| 12 | Hurricane | > 64 | Huge waves. Sea surface completely white. Visibility seriously affected by spray. | >16 |
Practical Applications of the Beaufort Scale:
- Navigation and Safety: How mariners use the scale to make decisions about setting sail, anchoring, or seeking shelter.
- Weather Forecasting: Integration of the scale in marine weather reports and its role in predicting severe weather conditions.
- Sailing Education: The importance of the Beaufort scale in sailing courses and certification programs.
Modern Use and Technological Integration:
- Technological Tools: Mention of how modern navigation tools and apps incorporate the Beaufort scale to aid mariners in real-time.
- Comparison with Other Systems: Brief comparison with other systems used in countries that do not predominantly use the Beaufort scale.
FAQ Section
Understanding and Using the Beaufort Scale
- What is the Beaufort scale and why is it important?
- The Beaufort scale is a standardized method for estimating and describing wind speeds and sea conditions. It helps mariners make informed decisions about sailing and safety.
- How do I interpret a Beaufort scale reading in a weather forecast?
- A forecast might say “Force 5 winds,” which translates to a fresh breeze with wind speeds between 17-21 knots and moderate waves. Familiarizing yourself with the scale will help you understand these terms.
- Is the Beaufort scale still used today?
- Yes, the Beaufort scale is still widely used in many countries, particularly in Europe and Asia, for marine weather forecasts. However, it is less commonly used in the United States.
- How can I learn the Beaufort scale?
- You can study the scale from charts like the one provided in this article, or use apps and online resources. Many sailing courses also include the Beaufort scale in their curriculum.
- Why does the United States not use the Beaufort scale as much as other countries?
- The United States has developed other methods and scales for weather forecasting, but the Beaufort scale remains a valuable tool globally and is still taught and recognized by mariners.
- How can the Beaufort scale affect my sailing plans?
- Knowing the wind force and sea conditions can help you decide whether it is safe to sail, plan your route, and prepare your vessel for expected conditions.
Editor’s Note: This article was originally published in September 2014 and was last updated in June 2024.
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