The Direct Answer
The cone of uncertainty shows the probable path of the center of a tropical cyclone over the next five days. It does not show the storm's size. It does not indicate where damage will occur. Areas outside the cone can — and regularly do — experience dangerous hurricane conditions.
How the Cone Is Constructed
The National Hurricane Center generates the cone using historical data on forecast errors going back to the previous five years. The cone is drawn so that the actual track of the storm's center falls within the cone approximately 60–70% of the time. That means there is a 30–40% chance the storm's center tracks outside the cone entirely.
What the Cone Does NOT Show
1. The Cone Is Not the Storm's Size
A major hurricane may have tropical-storm-force winds extending 300 miles from its center. The cone represents only where the center might go. If the cone's edge passes 100 miles from your city, your city may still experience sustained tropical storm winds, storm surge, and tornadoes spawned by the outer bands.
2. Areas Outside the Cone Are Not Safe
The NHC states this explicitly: "The cone does not represent the forecast uncertainty of the entire storm." People who see their location just outside the cone edge and decide not to prepare are making a potentially fatal mistake.
3. The Cone Does Not Show Intensity
A storm can be a Category 1 when it enters the cone and a Category 4 when it reaches your coastline. The shaded area carries no information about wind speed, storm surge, or rainfall.
4. The Cone Does Not Predict Landfall Location
The center of the cone is the most likely track — but it is a probabilistic forecast, not a guaranteed path. A slight shift of 30–50 miles in track can mean the difference between a direct hit and a near miss for a specific community.
How to Actually Use the Cone
The cone is one graphic in a full suite of NHC products. The storm surge watch/warning graphic, the wind speed probability graphic, and the written forecast discussion together give a far more complete picture of your risk.
If you are in a storm surge evacuation zone, your decision to evacuate should be based on your zone and the storm's surge potential — not on whether the cone's center passes over your exact address. Use our Storm Surge Lookup tool to check your specific risk.
Rather than asking "Is my city in the cone?" ask: Am I in a storm surge evacuation zone? What is the storm's forecast intensity at landfall? What are the rainfall and flooding threats? What does my local emergency manager say?
Frequently Asked Questions
Does being outside the cone mean I'm safe?
No. The cone only shows where the storm's center is likely to track. Hurricane-force winds, storm surge, and heavy rainfall can extend far beyond the cone's boundaries.
Why does the cone get wider over time?
Forecast uncertainty increases with time. The cone narrows near the present (higher certainty) and widens toward day 5 (lower certainty) to reflect the range of possible track outcomes.