What is the cone of uncertainty?

The cone of uncertainty is the National Hurricane Center's forecast for where the storm's center is likely to travel over the next several days. It isn't a guess — it's built directly from NHC's own historical forecast-error record over roughly the past five years. Take every forecast the agency has issued at a given range (say, 72 hours out), measure how far off the actual storm center ended up, and the cone is drawn to the size that would have contained most of those past errors.

That's why NHC describes it the way it does: historically, the storm's actual center stays inside the cone about two-thirds of the time. Two-thirds is a solid track record, but it also means roughly a third of the time, the real center ends up outside the cone entirely. It's a probability, not a promise.

This is where most people get it wrong. The cone is not the size of the storm, and it does not show where impacts — wind, rain, storm surge — will actually occur. It only tracks the probable path of a single point: the center of circulation.

A storm's damaging conditions routinely extend far outside the cone's edges, sometimes by hundreds of miles. Tropical-storm-force winds can reach well beyond the cone's boundary, heavy rain bands can train over areas nowhere near the forecast track, and storm surge can flood coastline that was never inside the cone at all. Being outside the cone is not the same as being safe.

Look at any cone graphic and you'll notice it's narrow near the storm's current position and flares out wider toward the outer days. That shape isn't arbitrary — it's a direct reflection of forecast confidence. A forecast for tomorrow is far more precise than a forecast five days out, because small errors in a storm's speed, direction, and strength compound the further out the forecast reaches. Near-term positions are tightly constrained; day-five positions cover a much wider swath of possibility.

This is exactly why waiting for the cone to "pinpoint" your exact town before you act is a mistake. By the time a storm is close enough for the cone to narrow down to your area, you may have very little time left to prepare, gather supplies, or evacuate. The cone widening at longer range isn't the forecast getting worse — it's the forecast being honest about what it can and can't know yet.

• Look at the whole width of the cone for your area — not just the thin center line. If any part of the cone touches your area, you're within the range of possible tracks, not automatically safe or automatically doomed.
• Check the separate impact maps. NHC publishes dedicated wind-probability, storm-surge, and rainfall forecast maps alongside the cone. These are the products that actually estimate where damaging conditions will occur — the cone alone can't tell you that.
• Watch the trend across several consecutive advisory updates rather than reacting to a single map. Forecasts shift advisory to advisory; a consistent trend over multiple updates tells you far more than any one snapshot.

For the fuller picture — watches vs. warnings, and why wind category alone doesn't tell you how dangerous a storm is — see Will it hit me? How to read the forecast. And if you want a plain-English breakdown of what each hurricane category actually means, read hurricane categories explained.

Does my area need to be inside the cone to be at risk?

No. The cone only tracks the storm's center. Damaging wind, rain, and storm surge extend well beyond it — sometimes hundreds of miles — so areas outside the cone can still face serious impacts.

How accurate is the cone?

It's drawn from NHC's own forecast-error history. The storm's actual center stays inside the cone about two-thirds of the time, historically — a good track record, but not a guarantee.

Why does the cone get wider farther out in time?

Because forecast confidence drops the further out you look. Tomorrow's position is much more predictable than day five's, so the cone narrows near the present and widens toward the outer days.

Where do I find the official cone graphic?

In NHC's public advisories at nhc.noaa.gov. HurriTrack links directly to the official NHC forecast for every active storm so you can check the source yourself.