Guesstimator grand-dad, Francis Beaufort, an English naval officer, in 1805, created the still-used wind scale. I had the full scale handy here.

He sort of made the reverse process than the one described above.

For your pleasure, the naval officer's scale:

Beaufort number, KPH/MPH, Description

0 0–2/0–1 Calm – smoke rises vertically, air feels still 1 2–6/1–3 Light air – smoke drifts 2 7–11/4–7 Slight breeze – wind detectable on face, some leaf movement 3 12–19/8–12 Gentle breeze – leaves and twigs move gently 4 20–29/13–18 Moderate breeze – loose paper blows about
5 30–39/19–24 Fresh breeze – small trees sway 6 40–50/25–31 Strong breeze – difficult to use an umbrella 7 51–61/32–38 High wind – whole trees bend 8 62–74/39–46 Gale – twigs break off trees, walking into wind is difficult 9 75–87/47–54 Strong gale – roof tiles blow away 10 88–101/55–63 Whole gale – trees break and are uprooted 11 102–119/64–74 Storm – damage is extensive, cars overturn 12 120+/75+ Hurricane – widespread devastation