Saffir-Simpson Hurricane Wind Scale

The scale assigns a hurricane a category from 1 to 5 according to its maximum sustained wind speed. In U.S. National Hurricane Center usage, the sustained wind measure is the maximum one-minute average at the standard observation height. The categories communicate wind intensity and the potential for wind damage; they are not a complete measure of a storm's overall danger or likely losses.

Category 1 corresponds to sustained winds of 74–95 miles per hour (119–153 kilometres per hour); Category 2, 96–110 mph (154–177 km/h); Category 3, 111–129 mph (178–208 km/h); Category 4, 130–156 mph (209–251 km/h); and Category 5, 157 mph or higher (252 km/h or higher). The National Hurricane Center calls Categories 3, 4 and 5 major hurricanes. Its damage descriptions progress from some damage at Category 1 to potentially catastrophic wind damage at the highest categories. These are generalized descriptions, not predictions for every individual building or location.

The rating is based on wind speed alone. It does not indicate how much storm surge or rainfall flooding a cyclone may produce, whether tornadoes will occur, how large the affected area is, or how long hazards will persist. A lower-category hurricane can still bring life-threatening coastal flooding, inland flooding or tornadoes. For this reason, the category should be considered alongside separate forecasts, watches, warnings and local emergency guidance.

The scale is a concise way to communicate a hurricane's strongest sustained winds and a broad indication of potential wind damage. It is not a linear measure: each category spans a wind-speed range, and damage depends on factors beyond the category, including exposure, construction and local conditions. Wind averaging periods also vary among meteorological agencies and basins, so category thresholds should be interpreted in the context of the issuing authority's stated convention.