Question: have we ever had a catergory 6 hurricane

Answer: No, A Category 5 Atlantic hurricane is one that is considered by the United States National Hurricane Center (NHC), to have had sustained wind speeds greater than 136 knots (157 mph; 252 km/h; 70 m/s) on the Saffir--Simpson scale. The NHC considers sustained wind speeds to be those that occur over a one-minute period at 10 metres (32.8 ft) above ground. These wind speeds are estimated by using a blend of data from a variety of sources, which include observations from nearby ships, reconnaissance aircraft, or automatic weather stations and pictures from various satellites.