Beaufort scale

The Beaufort scale is a scale for measuring wind speeds. It is based on observation rather than accurate measurement. It is the most widely used system to measure wind speed today. The scale was developed in 1805 by Francis Beaufort, an officer of the Royal Navy and first officially used by HMS Beagle.
There are twelve levels, plus 0 for "no wind". From 1946 to 1970, there were also beaufort levels 13 to 17. All of them were labelled as "Hurricane". Because they were only used in special cases, they are no longer in use internationally. China, and Taiwan still use them, because they often have typhoons. 
The wave heights given are for waves on the open ocean, not near the shore.
The Douglas Sea Scale and Douglas Wind Scale are similar, but they separate the sea from the wind.