| Beaufort No | Wind range | Wave Height | Description | Land Signs | Sea State | Dinghy |
| 0 | 0 to 1 knot (0-2 kph) | Flat | Calm | Smoke rises vertically, leaves do not stir. | Water calm, like a mirror. | Sails won't fill, racing flag limp, tell-tales flicker. |
| 1 | 1 to 3 knots (2-6 kph) | Ripples | Light air | Wind direction shown by smoke but not by wind vanes. | Ripples with the appearance of scales. | Sails fill, racing flags unreliable, tell-tales respond, crew and helmsman on opposite sides of boat. |
| 2 | 4 to 6 knots (7-11 kph) | 0.1 metres average, 0.3 metres maximum | Light breeze | Leaves rustle, wind felt on face, flags not extended, wind vanes moved by wind. | Small wavelets on water, crests have a glassy appearance and do not break. | Useful way made, racing flag reliable indicator, crew sit to windward. |
| 3 | 7 to 10 knots (12-19 kph) | 0.4 metres average, 1 metre maximum | Gentle breeze | Leaves and twigs in constant motion, wind extends light flag | Large wavelets, crests begin to break, maybe scattered whitecaps. | Crew and helmsman sit out to weather. Spinnakers fill, 14ft dinghies may plane. Easy sailing on all points. |
| 4 | 11 to 16 knots (20-30 kph) | 1 metre average, 1.5 metres maximum | Moderate breeze | Wind raises dust and loose paper, small branches move, flags extended. | Moderate waves, fairly frequent whitecaps. | Crews lie out, 12ft dinghies may plane, longer ones will, best general working breeze. |
| 5 | 17 to 21 knots (31-39 kph) | 2 metres average, 2.5 metres maximum | Fresh breeze | Small leafed trees begin to sway, tops of trees in motion. | Moderate, longer waves, many whitecaps, chance of spray. | Ease sheets in gusts, crew use all weight to keep upright, genoas near limit, some capsizes. |
| 6 | 22 to 27 knots (40-50kph) | 3 metres average, 4 metres maximum | Strong breeze | Large branches in motion, phone lines whistle. | Large waves form, white foam crests everywhere, probable spray. | Overpowered carrying full sail, crews find it difficult to hold craft upright even when spilling wind, many capsizes. |
| 7 | 28 to 33 knots (51-61 kph) | 4 metres average, 5.5 metres maximum | Near gale | Whole trees in motion, difficult to walk against wind. | Sea heaps up, white foam starts to blow in streaks. | Fully reefed, difficult to sail even on main alone. Go home. |
| 8 | 34 to 40 knots (62-74 kph) | 5.5 metres average, 7.5 metres maximum | Gale | Wind breaks twigs off trees, walking impeded. | Moderately high waves with crests beginning to break into foam that's blown in white streaks. | Survivable if expertly handled on foresail only. |
| 9 | 41 to 47 knots (75-87 kph) | 7 metres average, 10 metres maximum | Severe gale | Slight damage to buildings occurs, shingles torn off roofs. | High waves, rolling seas, dense streaks of foam, wave crests begin to topple, tumble and fall over. |
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| 10 | 48 to 55 knots (88-102 kph) | 9 metres average, 12.5 metres maximum | Storm | Trees uprooted, considerable structural damage to buildings. | High waves with overhanging crests, sea covered with large white patches of foam. |
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| 11 | 56 to 63 knots (103-117 kph) | 11 metres average, 16 metres maximum | Violent Storm | Widespread damage. | Huge waves, sea white with foam, air filled with spray, little visibility. |
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| 12 | 64+ knots (118+ kph) | 14 metres average, no maximum | Hurricane | Widespread damage | Exceptionally huge waves, sea white with foam, air filled with spray, little or no visibility. |
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