Very few countries in Europe use km/h. Instead weather forecasts are delivered with wind speed measured in m/s (meter per second). Getting a value of 30 km/h in the viewfinder requires some serious head calculations to swiftly understand the wind speed prior making a shot.
Ideally the wind speed should be selectable between m/s, km/h and mph. That would accommodate almost all players around the globe. Pretty much the same way you can set meter or yards.