When the maximum sustained winds of a tropical storm reach 74 miles per hour, it’s called a hurricane. Hurricane Season begins on June 1 and ends on November 30, but these powerful storms can occur before and after the official season. Hurricanes are rated by the Saffir-Simpson Hurricane Wind Scale as categories 1 through 5. The higher the category, the more dangerous the hurricane can be. Be prepared. Visit Ready.gov for hurricane tips.