# What is a hurricane?

 [](/facts/hurricanes-of.mp4) 

_

VIDEO: What is a hurricane? Here's what you need to know in less than a minute. [Transcript](#transcript)

_

A tropical cyclone is a rotating low-pressure weather system that has organized thunderstorms but no fronts (a boundary separating two air masses of different densities). Tropical cyclones with maximum sustained surface winds of less than 39 miles per hour (mph) are called tropical depressions. Those with maximum sustained winds of 39 mph or higher are called tropical storms.

When a storm's maximum sustained winds reach 74 mph, it is called a hurricane. The [Saffir-Simpson Hurricane Wind Scale](http://www.nhc.noaa.gov/aboutsshws.php) is a 1 to 5 rating, or category, based on a hurricane's maximum sustained winds. The higher the category, the greater the hurricane's potential for property damage.

Hurricanes originate in the Atlantic basin, which includes the Atlantic Ocean, Caribbean Sea, and Gulf of America, the eastern North Pacific Ocean, and, less frequently, the central North Pacific Ocean. A six-year rotating list of names, updated and maintained by the [World Meteorological Organization,](https://public.wmo.int/en) is used to identify these storms.

"Hurricane Season" begins on June 1 and ends on November 30, although hurricanes can, and have, occurred outside of this time frame. NOAA's [National Hurricane Center](http://www.nhc.noaa.gov/) predicts and tracks these massive storm systems, which occur, on average, 12 times a year in the Atlantic basin.

As a world leader in hurricane research, NOAA strives to understand the mechanics of these complex storms in order to protect people, property, commerce, and natural resources.

## Video Transcript

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. A hurricane can be an awesome and destructive force of nature. Be prepared. Visit Ready.gov

Did you know? - The [National Coastal Zone Management Program](https://coast.noaa.gov/czm/) is a state and federal partnership program that addresses the nation’s coastal issues. The [National Estuarine Research Reserve System](https://coast.noaa.gov/nerrs/) protects estuaries and provides educational and science opportunities.

- [What is the difference between a hurricane watch and a warning?](https://oceanservice.noaa.gov/facts/watch-warning.html)

- [Why do we name tropical storms?](https://oceanservice.noaa.gov/facts/storm-names.html)

- [National Hurricane Center](http://www.nhc.noaa.gov/)

- [Ready.gov](https://www.ready.gov/)

- 

- **Partners:** *California Coastal Conservancy, Minnesota Lake Superior Coastal Program, Puerto Rico Coastal Zone Management Program, and Virginia Coastal Zone Management Program; the Elkhorn Slough, Grand Bay, Narragansett Bay, San Francisco, Waquoit Bay, and Wells National Estuarine Research Reserves; and Access Adventure at Rush Ranch, Boston University Graduate Program in Deaf Education, City of Duluth, Governor Baxter School for the Deaf, Horace Mann School for the Deaf, Isle of Wight County, Punta Tuna Nature Reserve, READS Collaborative, Rhode Island School for the Deaf, Solano Land Trust, and The Learning Center for the Deaf’s Center for Research and Training and Marie Philip School.*