Hurricane categories, explained simply
In 30 seconds. A hurricane's category, from 1 to 5, is based only on its sustained wind speed. It says nothing directly about rain or storm surge, which often cause the worst damage.
Key points
- Categories come from the Saffir-Simpson scale and use sustained wind speed only.
- Category 1 starts at 74 mph; Category 5 starts at 157 mph.
- Storm surge and flooding rain are not part of the category, and they cause most hurricane deaths.
- The National Hurricane Center in Miami issues the official U.S. forecasts and warnings.
What happened
Every Atlantic hurricane season, from June 1 to November 30, forecasts announce that a storm has strengthened or weakened by category. The number becomes the headline, even though it captures only one of the storm's dangers.
The scale, category by category
Category 1: 74 to 95 mph winds. Category 2: 96 to 110 mph. Category 3: 111 to 129 mph, the point where a storm is called major. Category 4: 130 to 156 mph. Category 5: 157 mph and above. As wind speed rises, potential damage grows far faster than the numbers suggest, because wind force increases sharply with speed.
What the category leaves out
The scale does not measure storm surge, the wall of seawater a hurricane pushes ashore, or rainfall flooding far inland. Slow moving lower category storms have produced catastrophic floods. Officials therefore warn residents to judge a storm by local surge and rain forecasts, not by category alone.
Why it matters
Evacuation orders, insurance decisions and news coverage all lean on the category, so misunderstanding it has real costs. A downgrade from Category 4 to Category 2 at landfall sounds like relief, yet the water the storm is carrying does not downgrade with the wind.
What happens next
During any storm, the most useful updates are the National Hurricane Center advisories issued every few hours: they carry the wind speed, the forward speed, and the specific surge and rainfall forecasts for each stretch of coast.
National Hurricane Center, Saffir-Simpson Hurricane Wind Scale documentation and tropical cyclone advisories; National Weather Service hurricane preparedness guidance. Linked in full at publication.