Wind speed
The Beaufort Scale ( /ˈboʊfərt/) is an empirical measure for describing wind speed based mainly on observed sea conditions (on land it is categorised by the physical effects it has on vegetation and structures). Its full name is the Beaufort Wind Force Scale. Read more 
Wind speed, or wind velocity, is a fundamental atmospheric rate. Wind speed affects weather forecasting, aircraft and maritime operations, construction projects, growth and metabolism rate of many plant species, and countless other implications. Wind speed is now commonly measured with an anemometer but can also be classified using the older Beaufort scale which is based on people's observation of specifically defined wind effects.
Read more 