Exercise 1: Saffir-Simpson Scale Let's learn about what the different categories of hurricane mean. In short, it all comes down to wind speed. The upper bounds are non-inclusive for example, a category Four is 58 (included) up to but not including 70 m/s. Category Wind Speed Five 70 m/s Four 5870 m/s Three 50-58 m/s Two 43-50 m/s One 33-43 m/s Tropical Storm 1833 m/s Tropical Depression