Beaufort Scale

Beaufort number>	Wind speed				Description	Wave height		Sea conditions	Land conditions	Sea state photo
	km/h	mph	kts	m/s		m	ft
0	<1	<1	<1	<0.3	Calm	0	0	Flat.	Calm. Smoke rises vertically.
1	1-5	1-3	1-2	0.3-1.5	Light air	0.1	0.33	Ripples without crests.	Wind motion visible in smoke.
2	6-11	3-7	3-6	1.5-3.3	Light breeze	0.2	0.66	Small wavelets. Crests of glassy appearance, not breaking	Wind felt on exposed skin. Leaves rustle.
3	12-19	8-12	7-10	3.3-5.5	Gentle Breeze	0.6	2	Large wavelets. Crests begin to break; scattered whitecaps	Leaves and smaller twigs in constant motion.
4	20-28	13-17	11-15	5.5-8.0	Moderate breeze	1	3.3	Small waves.	Dust and loose paper raised. Small branches begin to move.
5	29-38	18-24	16-20	8.0-10.8	Fresh breeze	2	6.6	Moderate (1.2 m) longer waves. Some foam and spray.	Branches of a moderate size move. Small trees begin to sway.
6	39-49	25-30	21-26	10.8-13.9	Strong breeze	3	9.9	Large waves with foam crests and some spray.	Large branches in motion. Whistling heard in overhead wires. Umbrella use becomes difficult.
7	50-61	31-38	27-33	13.9-17.2	High wind, Moderate Gale, Near Gale	4	13.1	Sea heaps up and foam begins to streak.	Whole trees in motion. Effort needed to walk against the wind.
8	62-74	39-46	34-40	17.2-20.7	Fresh Gale	5.5	18	Moderately high waves with breaking crests forming spindrift. Streaks of foam.	Twigs broken from trees. Cars veer on road.
9	75-88	47-54	41-47	20.7-24.5	Strong Gale	7	23	High waves (6-7 m) with dense foam. Wave crests start to roll over. Considerable spray.	Larger branches break off trees, and some small trees blow over. Construction/temporary signs and barricades blow over. Damage to circus tents and canopies.
10	89-102	55-63	48-55	24.5-28.4	Whole Gale/Storm	9	29.5	Very high waves. 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.	Trees are broken off or uprooted, saplings become bent and/or deformed, poorly attached asphalt shingles and shingles in poor condition peel off roofs.
11	103-117	64-72	56-63	28.4-32.6	Violent storm	11.5	37.7	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.	Widespread vegetation damage. Many roof shingles and surfaces sustain damage; gravel may be blown from flat roofs.
12	≥118	≥73	≥64	≥32.6	Hurricane	≥14	≥46	Huge waves. Sea is completely white with foam and spray. Air is filled with driving spray, greatly reducing visibility.	Considerable and widespread damage to vegetation, a few windows broken, structural damage to mobile homes and poorly constructed sheds and barns. Debris may be hurled about.