Saffir-Simpson Hurricane Wind Scale

The Saffir-Simpson Hurricane Wind Scale rates Atlantic and eastern Pacific hurricanes 1 to 5 by sustained one-minute surface wind. Category 1 begins at 64 knots (74 mph); Category 3 (major) at 96 knots; Category 5 at 137 knots and above. Since 2010 the scale is wind-only; storm surge and flooding are forecast separately. Mariners use it for avoidance planning, since the dangerous semicircle and the 34-, 50-, and 64-knot wind radii drive the safe distance to keep from the track.