Because spring is the windiest season of the year, it's a relevant time to talk about the Beaufort scale, the oldest method of judging the force of the wind.

This scale runs from 0 to 12, and was devised in 1805 by Sir Francis Beaufort of the British Navy. In original form, the scale measured the force of the wind, not its speed, based on the wind's effect on a sailing ship. The scale was later correlated to wind speed and the effects the wind has on the sea surface and on objects such as trees. As an example, Beaufort force 4 winds, called a "moderate breeze", are 13 to 18 mph, enough to move small branches on trees and create small waves and numerous whitecaps on the sea.

Just for reference, so-called "gale-force" or "tropical-storm-force" winds of 39 mph correspond to Beaufort force 8, while hurricane winds of 74 mph are Beaufort force 12.