Saffir-Simpson Hurricane Scale Explained: What Each Category Means

The Saffir-Simpson hurricane scale, officially the Saffir-Simpson Hurricane Wind Scale, is the 1-to-5 rating the National Hurricane Center (NHC) uses to describe a hurricane’s strength. It is based on one number only: the storm’s maximum sustained wind. A Category 1 hurricane has sustained winds of 74 to 95 mph, while a Category 5 has winds of 157 mph or higher.

What the scale does not do is just as important. It says nothing about storm surge, rainfall flooding or tornadoes, which can be deadly in any hurricane. This guide walks through each category using the NHC’s own descriptions and shows how to read a category without overreacting or underreacting.

What is the Saffir-Simpson Hurricane Wind Scale?

According to the National Hurricane Center’s official scale page, the Saffir-Simpson Hurricane Wind Scale is a 1 to 5 rating based only on a hurricane’s maximum sustained wind speed, and it estimates potential property damage. The scale was originally developed by wind engineer Herb Saffir and meteorologist Bob Simpson, and the NHC describes it as a tool for alerting the public to the possible impacts of hurricanes of different intensities.

The key measurement is the maximum sustained surface wind. The NHC defines it as the highest one-minute average wind at a standard height of 10 meters (about 33 feet) over unobstructed exposure. A brief gust can be stronger, but only the sustained wind sets the category.

Why the word “Wind” is in the name

Earlier versions, known simply as the Saffir-Simpson Hurricane Scale, also included central pressure and storm surge ranges for each category. The NHC explains that central pressure served as a stand-in for wind speed in the 1970s and 1980s, before aircraft wind measurements were routine, and that storm surge ranges appeared in the earliest published versions in the early 1970s.

Real storms did not fit those surge ranges well, because surge depends on a hurricane’s size, forward speed, angle of approach and the local coastline. The NHC’s background document contrasts two historical storms: the very large Hurricane Ike (2008) came ashore in Texas as a Category 2 with a peak surge of about 20 feet, while the compact Hurricane Charley (2004) struck Florida as a Category 4 with a peak surge of only about 7 feet. To reduce public confusion, surge, flooding and pressure statements were removed, and only peak winds remain in the current Saffir-Simpson Hurricane Wind Scale.

Categories 1 to 5 at a glance

Official NHC wind ranges in miles per hour, knots and kilometers per hour, with a short summary of the wind damage the NHC associates with each category:

What each hurricane category means

Category 1: very dangerous winds

Even the lowest category is not a minor event. The NHC warns that flying or falling debris can injure or kill people and animals at Category 1, and that older mobile homes that are not properly anchored can shift or roll off their foundations. Large branches will snap, and damage to power lines and poles is likely to cause outages lasting a few to several days.

Category 2: extremely dangerous winds

At 96 to 110 mph, many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected for several days to weeks, and the NHC notes that potable water could become scarce as filtration systems begin to fail.

Category 3: the first major hurricane level

At 111 to 129 mph, the NHC’s wording shifts to “devastating damage will occur.” Well-built framed homes may lose roof decking and gable ends, and electricity and water will be unavailable for several days to weeks after the storm passes.

Categories 4 and 5: catastrophic damage

Category 4 (130 to 156 mph) can strip most of the roof structure and some exterior walls from well-built homes. Category 5 starts at 157 mph and has no upper limit; the NHC says a high percentage of framed homes will be destroyed, with total roof failure and wall collapse. In both, fallen trees and power poles isolate neighborhoods, outages last weeks to possibly months, and most of the area can be uninhabitable for weeks or months. In the western North Pacific, the NHC notes, “super typhoon” is used for tropical cyclones with sustained winds exceeding 150 mph.

What is a major hurricane?

The NHC classifies any hurricane at Category 3 or higher as a major hurricane. That means sustained winds of at least 111 mph (96 kt). The agency says major hurricanes can cause devastating to catastrophic wind damage and significant loss of life simply because of the strength of their winds.

That label should not make Category 1 or 2 storms sound safe. The NHC stresses that all hurricanes produce life-threatening winds. Its background document also says that, in general, wind damage rises by about a factor of four for every one-category increase, which is why a single step on the scale matters so much.

What the scale does not tell you

The NHC is explicit: the Saffir-Simpson scale does not account for storm surge, rainfall flooding or tornadoes. Hurricanes of all categories can produce deadly surge, rain-induced floods and tornadoes, and those hazards can require people to take protective action, including evacuating from areas vulnerable to storm surge. Ready.gov adds that storm surge has historically been the leading cause of hurricane-related deaths in the United States.

Several other limits are worth knowing:

• Winds vary by location. The category reflects the storm’s peak sustained wind at a given time, not the wind every community will feel. The NHC notes that peak winds are believed to drop by about one category within roughly half a mile to a kilometer inland from the coastline, although exceptions are possible.
• Buildings matter. The damage descriptions depend partly on local building codes and how well they have been enforced. Newer construction built to stronger codes may fare better than older housing stock.
• Duration and size matter. The NHC says wind damage also depends on how long high winds last, changes in wind direction and the age of structures. A large, slow storm can cause more harm than its category suggests.

How the scale relates to tropical storms and hurricanes

The scale only applies once a storm is a hurricane. The NHC glossary sets the thresholds by maximum sustained wind, using a one-minute average:

• Tropical depression: 38 mph (33 kt) or less.
• Tropical storm: 39 to 73 mph (34 to 63 kt). Tropical storms carry no Saffir-Simpson category.
• Hurricane: 74 mph (64 kt) or more, which is where Category 1 begins.

Because tropical storms sit below the scale, a storm described as “just a tropical storm” can still bring flooding rain, surge and tornadoes.

How the National Hurricane Center uses the scale

NHC forecasters assign a storm’s intensity in 5-knot increments because of the uncertainty in estimating tropical cyclone strength. For advisories that use miles per hour and kilometers per hour, that value is converted and rounded to the nearest 5 mph or 5 km/h, so the agency does not imply false precision.

That rounding explains a small 2012 change. The NHC broadened the Category 4 range by 1 mph at each end, to 130 to 156 mph, so that a storm rated 115 kt converts cleanly to 130 mph and stays in Category 4 in every unit. The NHC says the adjustment did not change the category of any storm in the historical record.

The category is one piece of an advisory, not the whole message. Watches and warnings are issued separately and do not depend on category; any hurricane can prompt them. For a plain-English breakdown of those alerts, see our guide to hurricane watches versus warnings.

What to do with the category information

Use the category as a signal of potential wind damage, then look at the full picture for your area. Practical steps drawn from NHC and Ready.gov guidance include:

• Learn whether you live in an evacuation zone, since surge risk is not captured by the category.
• Follow instructions from local emergency managers, and leave immediately if officials order an evacuation for your area.
• Keep several ways to receive alerts, including Wireless Emergency Alerts and NWS notifications.
• Plan for outages that can last days to weeks, even in lower-category storms, with supplies, medications and charged devices.

For ongoing forecasts, radar and alert coverage across the country, LiveNewsWorld’s U.S. Weather Live center collects severe weather updates in one place, and the Watch Live News hub lists national live coverage options.

The bottom line

The Saffir-Simpson Hurricane Wind Scale is a fast way to understand how damaging a hurricane’s winds could be. Category 1 begins at 74 mph, Category 3 marks a major hurricane, and Category 5 starts at 157 mph.

But a category is a wind rating, not a full risk score. Storm surge, flooding rain and tornadoes can be deadly at any category, and local conditions can make a storm far worse than its number implies. Treat the category as one input, keep watching official NHC advisories, and let local emergency officials guide decisions about sheltering or evacuating.

Sources

• National Hurricane Center, Saffir-Simpson Hurricane Wind Scale (NOAA)
• National Hurricane Center, The Saffir-Simpson Hurricane Wind Scale (background document, PDF) and 2012 minor modification (PDF)
• National Hurricane Center, Glossary of NHC Terms
• Ready.gov, Hurricanes (FEMA)