19-24 Mph 29-38 kph 17-21 knots Fresh Breeze Small trees sway. White crested wavelets (whitecaps) form, some spray. 25-31 Mph 39-49 kph 22-27 knots Strong Breeze Large tree branches move, telephone wires begin to "whistle", umbrellas are difficult to keep under control. Larger waves form, whitecaps prevalent, spray.