Saffir-Simpson scale
The scale classifies a hurricane by maximum one minute sustained wind only. It says nothing about rainfall, storm surge or the size of the system.
Official warnings come from the National Hurricane Center and your local emergency agency. This page is informational and does not replace an official advisory.
| Category | kt | km/h | mph | What it means |
|---|---|---|---|---|
| Tropical depression | 0–33 | 0–61 | 0–38 | Heavy rain and wind below 39 mph. |
| Tropical storm | 34–63 | 63–117 | 39–72 | Wind of 39 to 73 mph, downed trees, flooding. |
| Category 1 | 64–82 | 119–152 | 74–94 | Roof and gutter damage, broken branches, power cuts. |
| Category 2 | 83–95 | 154–176 | 96–109 | Major roof damage, uprooted trees, outages lasting days. |
| Category 3 (major hurricane) | 96–112 | 178–207 | 110–129 | Homes lose roof decking; water and power out for weeks. |
| Category 4 | 113–136 | 209–252 | 130–157 | Exterior walls destroyed; area uninhabitable for weeks or months. |
| Category 5 | ≥ 137 | ≥ 254 | ≥ 158 | Homes destroyed; the area stays uninhabitable for months. |
- NOAA National Hurricane CenterLicence: Domínio público (dado federal dos EUA) · Credit: NOAA / National Hurricane CenterOs avisos oficiais estão em nhc.noaa.gov. Esta página não substitui o aviso oficial.
How to read these numbers
Category 3 and above is called a major hurricane by the NHC. The relation between wind and damage is not linear: category 4 wind carries roughly four times the damage potential of category 1.
Most hurricane deaths come from water, not wind: storm surge and inland flooding. A slow category 1 can therefore kill more people than a fast category 4.
Frequently asked questions
- Is there a category 6?
- Not on the official scale. The academic discussion about adding a band above 190 knots has not been adopted by the NHC.
- Why does the category drop before landfall?
- Cooler water, dry air and shear weaken the system, but the storm surge already built up keeps coming.