see this post DIY Zigbee weather station - Share your Projects! - Home Assistant Community (home-assistant.io)
The windforce is indicated in Dutch but I guess you can translate that yourselves
sensors:
windforce:
friendly_name: Wind force
icon_template: " mdi:weather-windy"
value_template: "{% set wind = states('sensor.windspeed')|float %}
{% set wind_round = wind|round(1) %}
{% if wind <= 1 %}Bft: 0, Wind stil, {{wind_round}} m/s
{% elif wind <= 5 %}Bft: 1
, Zwak: flauwe wind, {{wind_round}} m/s
{% elif wind <= 11 %}Bft: 2, Zwak, {{wind_round}} m/s
{% elif wind <= 20 %}Bft: 3, Matig: lichte bries, {{wind_round}} m/s
{% elif wind <= 28 %}Bft: 4, Matig: flauwe bries, {{wind_round}} m/s
{% elif wind <= 39 %}Bft: 5, Vrij krachtig, {{wind_round}} m/s
{% elif wind <= 50 %}Bft: 6, Krachtig, {{wind_round}} m/s
{% elif wind <= 62 %}Bft: 7, Hard, {{wind_round}} m/s
{% elif wind <= 75 %}Bft: 8, Stormachting, {{wind_round}} m/s
{% elif wind <= 89 %}Bft: 9, Storm, {{wind_round}} m/s
{% elif wind <= 103 %}Bft: 10, Zware storm, {{wind_round}} m/s
{% elif wind <= 117 %}Bft: 11, Zeer zware storm, {{wind_round}} m/s
{% else %} > 117 %}Bft: 12, Orkaan, {{wind_round}} m/s
{%- endif %}"