A Category 5 hurricane requires minimum sustained winds of 157 mph. On the Saffir–Simpson Hurricane Wind Scale, Category 5 is the highest classification and has no upper wind-speed limit.
The threshold refers to maximum sustained wind averaged over one minute, measured at a standard height of 10 meters above the surface. The scale is used for hurricanes in the Atlantic, eastern North Pacific, and central North Pacific basins. It classifies storms by wind speed alone, not by storm surge, rainfall, flooding, or the size of the hurricane.
The most common mix-up is the nearby Category 4 range: Category 4 ends at 156 mph, while 157 mph begins Category 5. Values such as 165 mph are also Category 5, but they are not the minimum required speed. A storm’s category can change as its sustained winds strengthen or weaken.
Category 3 and above are called major hurricanes, but Category 5 storms are in a different league of wind damage. They can cause catastrophic destruction, including widespread roof failure and the collapse of some buildings. Even so, a lower-category storm can cause greater overall harm if flooding, rainfall, surge, or location is more severe.