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Terms used to describe coastal weather and the ocean. Note that 1.0 knot = 1.85 kilometre/hour
Wind and warning categories
(wind speed refers to the average over a 10-minute period, 10 metres above the surface.
Gusts may be up to 40 per cent stronger than the average speed.)
Category |
Speed | Beaufort force |
| Strong wind warning1 |
25-33 knots | 6-7 |
| Gale warning | 34-47 knots |
8-9 |
| Storm warning |
> 47 knots | 10-11 |
| Hurricane warning2 |
> 63 knots | 12 |
| 1 Strong wind warning for coastal waters area only. |
| 2 Hurricane warning for tropical high seas area only. |
Sea wave categories (open sea)
(Wave height is the vertical distance between the top of the crest and the bottom of the trough.)
Category |
Height |
| Slight |
0.5 - 1.25 metres |
| Moderate |
1.25 - 2.5 metres |
| Rough |
2.5 - 4.0 metres |
| Very rough |
4.0 - 6.0 metres |
| High |
6.0 - 9.0 metres |
| Very high |
9.0 - 14.0 metres |
| Phenomenal |
14 metres or more |
Swell categories
(Wave and swell heights are described in terms of significant wave height, which represents the average
of the highest one-third of waves. Some waves will be higher and some will be lower than the significant wave height.
Typically, one in 2000 waves will be twice this height.)
Category |
Wave length |
| Short |
0-100 metres |
| Average |
100-200 metres |
| Long |
> 200 metres |
Category |
Wave height |
| Low |
0-2 metres |
| Moderate |
2-4 metres |
| Heavy |
> 4 metres |
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