Go to the Main Menu from the Home screen of the app, and from there to Settings and Units. Here you can select: Wind speed: m/s (meters per second), mph (miles per hour), kph (kilometers per hour), kts (knots: 1 nautical mile per hour, 1.852 kmh, 1.15078 mph or 0.514 m/s), beaufort (Beaufort wind force scale).